TUAN ANH NGUYEN et al. v. IMMIGRATION AND NATURALIZATION SERVICE

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TUAN ANH NGUYEN et al. v. IMMIGRATION AND
NATURALIZATION SERVICE
certiorari to the united states court of appeals for
the fifth circuit
No. 99–2071. Argued January 9, 2001—Decided June 11, 2001
Petitioner Tuan Anh Nguyen was born out of wedlock in Vietnam to a
Vietnamese citizen and copetitioner Joseph Boulais, a United States
citizen. Nguyen became a lawful permanent United States resident at
age six and was raised by Boulais. At age 22, Nguyen pleaded guilty
in a Texas state court to two counts of sexual assault on a child. Sub-
sequently, respondent Immigration and Naturalization Service initiated
deportation proceedings against him based on his serious criminal
offenses. The Immigration Judge ordered him deportable. Boulais
obtained an order of parentage from a state court while Nguyen’s appeal
was pending before the Board of Immigration Appeals, but the Board
dismissed the appeal, rejecting Nguyen’s citizenship claim because he
had not complied with 8 U. S. C. § 1409(a)’s requirements for one born
out of wedlock and abroad to a citizen father and a noncitizen mother.
On appeal, the Fifth Circuit rejected petitioners’ claim that § 1409
violates equal protection by providing different citizenship rules for
children born abroad and out of wedlock depending on whether the
citizen parent is the mother or the father.
Held: Section 1409 is consistent with the equal protection guarantee
embedded in the Fifth Amendment’s Due Process Clause. Pp. 59–73.
(a) A child born abroad and out of wedlock acquires at birth the
nationality status of a citizen mother who meets a specified residency
requirement. § 1409(c). However, when the father is the citizen par-
ent, inter alia, one of three affirmative steps must be taken before the
child turns 18: legitimization, a declaration of paternity under oath
by the father, or a court order of paternity. § 1409(a)(4). The fail-
ure to satisfy this section renders Nguyen ineligible for citizenship.
Pp. 59–60.
(b) A gender-based classification withstands equal protection scru-
tiny if it serves important governmental objectives and the discrimi-
natory means employed are substantially related to the achieve-
ment of those objectives. United States v. Virginia, 518 U. S. 515, 533.
Congress’ decision to impose different requirements on unmarried
fathers and unmarried mothers is based on the significant difference be-
tween their respective relationships to the potential citizen at the time

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54 TUAN ANH NGUYEN v. INS
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of birth and is justified by two important governmental interests.
Pp. 60–71.
(1) The first such interest is the importance of assuring that a
biological parent-child relationship exists. The mother’s relation is
verifiable from the birth itself and is documented by the birth certificate
or hospital records and the witnesses to the birth. However, a father
need not be present at the birth, and his presence is not incontrovertible
proof of fatherhood. See Lehr v. Robertson, 463 U. S. 248, 260, n. 16.
Because fathers and mothers are not similarly situated with regard
to proof of biological parenthood, the imposition of different rules for
each is neither surprising nor troublesome from a constitutional per-
spective. Section 1409(a)(4)’s provision of three options is designed to
ensure acceptable documentation of paternity. Petitioners argue that
§ 1409(a)(1)’s requirement that a father provide clear and convincing
evidence of parentage is sufficient to achieve the end of establishing
paternity, given the sophistication of modern DNA tests. However,
that section does not mandate DNA testing. Moreover, the Constitu-
tion does not require that Congress elect one particular mechanism
from among many possible methods of establishing paternity, and
§ 1409(a)(4) represents a reasonable legislative conclusion that the
satisfaction of one of several alternatives will suffice to establish the
father-child blood link required as a predicate to the child’s acquisi-
tion of citizenship. Finally, even a facially neutral rule would some-
times require fathers to take additional affirmative steps which would
not be required of mothers, whose names will be on the birth certificate
as a result of their presence at the birth, and who will have the benefit
of witnesses to the birth to call upon. Pp. 62–64.
(2) The second governmental interest furthered by § 1409(a)(4) is
the determination to ensure that the child and citizen parent have some
demonstrated opportunity to develop a relationship that consists of real,
everyday ties providing a connection between child and citizen parent
and, in turn, the United States. Such an opportunity inheres in the
event of birth in the case of a citizen mother and her child, but does not
result as a matter of biological inevitability in the case of an unwed
father. He may not know that a child was conceived, and a mother
may be unsure of the father’s identity. One concern in this context
has always been with young men on duty with the Armed Forces in
foreign countries. Today, the ease of travel and willingness of Ameri-
cans to visit foreign countries have resulted in numbers of trips abroad
that must be of real concern when contemplating the prospect of man-
dating, contrary to Congress’ wishes, citizenship by male parentage sub-
ject to no condition other than the father’s residence in this country.
Equal protection principles do not require Congress to ignore this

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reality. Section 1409 takes the unremarkable step of ensuring that the
opportunity inherent in the event of birth as to the mother-child re-
lationship exists between father and child before citizenship is con-
ferred upon the latter. That interest’s importance is too profound to
be satisfied by a DNA test because scientific proof of biological pater-
nity does not, by itself, ensure father-child contact during the child’s
minority. Congress is well within its authority in refusing, absent
proof of an opportunity for a relationship to develop, to commit this
country to embracing a child as a citizen. Contrary to petitioners’ ar-
gument, § 1409 does not embody a gender-based stereotype. There is
nothing irrational or improper in recognizing that at the moment of
birth—a critical event in the statutory scheme and tradition of citi-
zenship law—the mother’s knowledge of the child and the fact of par-
enthood have been established in a way not guaranteed to the unwed
father. Pp. 64–68.
(3) The means Congress chose substantially relate to its interest
in facilitating a parent-child relationship. First, various statutory pro-
visions, in addition to § 1409(a), require that some act linking a child to
the United States occur before the child turns 18. Second, petitioners’
argument that § 1409(a)(4) reflects a stereotype that women are more
likely than men to actually establish the required relationship mis-
conceives both the governmental interest’s nature and the equal pro-
tection inquiry. As to the former, Congress could have chosen to ad-
vance the interest of ensuring a meaningful relationship in every
case, but it enacted instead an easily administered scheme to promote
the different but still substantial interest of ensuring an opportunity
for that relationship to develop. Petitioners’ argument confuses the
equal protection inquiry’s means and ends; § 1409(a)(4) should not be
invalidated because Congress elected to advance an interest that is
less demanding to satisfy than some alternative. Even if one conceives
of Congress’ real interest as the establishment of a meaningful relation-
ship, it is almost axiomatic that a policy seeking to foster the opportu-
nity for meaningful parent-child bonds to develop has a close and sub-
stantial bearing on the governmental interest in that bond’s formation.
Here, Congress’ means are in substantial furtherance of an important
governmental objective, and the fit between the means and that end is
exceedingly persuasive. See Virginia, supra, at 533. Pp. 68–70.
(c) Section 1409(a)(4) imposes a minimal obligation. Only the least
onerous of its three options must be satisfied; and it can be satisfied on
the day of birth, or the next day, or for the next 18 years. Section
1409(a), moreover, is not the sole means of attaining citizenship for the
child, who can seek citizenship in his or her own right, rather than via
reliance on parental ties. Pp. 70–71.

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(d) Because the statute satisfies the equal protection scrutiny applied
to gender-based qualifications, this Court need not consider whether it
can confer citizenship on terms other than those specified by Congress
or assess the implications of statements in earlier cases regarding the
wide deference afforded to Congress in exercising its immigration and
naturalization power. Pp. 71–73.
208 F. 3d 528, affirmed.
Kennedy, J., delivered the opinion of the Court, in which Rehnquist,
C. J., and Stevens, Scalia, and Thomas, JJ., joined. Scalia, J., filed a
concurring opinion, in which Thomas, J., joined, post, p. 73. O’Connor,
J., filed a dissenting opinion, in which Souter, Ginsburg, and Breyer,
JJ., joined, post, p. 74.
Martha F. Davis argued the cause for petitioners. With
her on the briefs were Nancy A. Falgout, Steven R. Shapiro,
Lucas Guttentag, Julie Goldscheid, and Sherry J. Leiwant.
Deputy Solicitor General Kneedler argued the cause for
respondent. With him on the brief were Solicitor General
Waxman, Assistant Attorney General Ogden, Austin C.
Schlick, Michael Jay Singer, and John S. Koppel.*
Justice Kennedy delivered the opinion of the Court.
This case presents a question not resolved by a majority of
the Court in a case before us three Terms ago. See Miller v.
Albright, 523 U. S. 420 (1998). Title 8 U. S. C. § 1409 gov-
erns the acquisition of United States citizenship by persons
born to one United States citizen parent and one noncitizen
parent when the parents are unmarried and the child is born
outside of the United States or its possessions. The statute
imposes different requirements for the child’s acquisition
of citizenship depending upon whether the citizen parent is
*Briefs of amici curiae urging reversal were filed for Equality Now
et al. by Ogden Northrup Lewis and Jessica Neuwirth; and for the
National Women’s Law Center et al. by Nancy Duff Campbell, Joan
Entmacher, Dina R. Lassow, and Nancy L. Perkins.
Moses Silverman and Kenneth Kimerling filed a brief for the Asian
American Legal Defense and Education Fund, Inc., as amicus curiae.

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the mother or the father. The question before us is whether
the statutory distinction is consistent with the equal pro-
tection guarantee embedded in the Due Process Clause of
the Fifth Amendment.
I
Petitioner Tuan Anh Nguyen was born in Saigon, Vietnam,
on September 11, 1969, to copetitioner Joseph Boulais and a
Vietnamese citizen. Boulais and Nguyen’s mother were not
married. Boulais always has been a citizen of the United
States, and he was in Vietnam under the employ of a corpo-
ration. After he and Nguyen’s mother ended their rela-
tionship, Nguyen lived for a time with the family of Boulais’
new Vietnamese girlfriend. In June 1975, Nguyen, then
almost six years of age, came to the United States. He be-
came a lawful permanent resident and was raised in Texas
by Boulais.
In 1992, when Nguyen was 22, he pleaded guilty in a Texas
state court to two counts of sexual assault on a child. He
was sentenced to eight years in prison on each count. Three
years later, the United States Immigration and Naturaliza-
tion Service (INS) initiated deportation proceedings against
Nguyen as an alien who had been convicted of two crimes
involving moral turpitude, as well as an aggravated felony.
See 8 U. S. C. §§ 1227(a)(2)(A)(ii) and (iii) (1994 ed., Supp. IV).
Though later he would change his position and argue he was
a United States citizen, Nguyen testified at his deportation
hearing that he was a citizen of Vietnam. The Immigration
Judge found him deportable.
Nguyen appealed to the Board of Immigration Appeals
and, in 1998, while the matter was pending, his father ob-
tained an order of parentage from a state court, based on
DNA testing. By this time, Nguyen was 28 years old. The
Board dismissed Nguyen’s appeal, rejecting his claim to
United States citizenship because he had failed to establish
compliance with 8 U. S. C. § 1409(a), which sets forth the re-

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quirements for one who was born out of wedlock and abroad
to a citizen father and a noncitizen mother.
Nguyen and Boulais appealed to the Court of Appeals for
the Fifth Circuit, arguing that § 1409 violates equal protec-
tion by providing different rules for attainment of citizenship
by children born abroad and out of wedlock depending upon
whether the one parent with American citizenship is the
mother or the father. The court rejected the constitutional
challenge to § 1409(a). 208 F. 3d 528, 535 (2000).
The constitutionality of the distinction between unwed
fathers and mothers was argued in Miller, but a majority
of the Court did not resolve the issue. Four Justices, in
two different opinions, rejected the challenge to the gender-
based distinction, two finding the statute consistent with
the Fifth Amendment, see 523 U. S., at 423 (opinion of Ste-
vens, J., joined by Rehnquist, C. J.), and two conclud-
ing that the court could not confer citizenship as a remedy
even if the statute violated equal protection, see id., at 452
(Scalia, J., joined by Thomas, J., concurring in judgment).
Three Justices reached a contrary result, and would have
found the statute violative of equal protection. Id., at 460
(Ginsburg, J., joined by Souter and Breyer, JJ., dissent-
ing); id., at 471 (Breyer, J., joined by Souter and Gins-
burg, JJ., dissenting). Finally, two Justices did not reach
the issue as to the father, having determined that the
child, the only petitioner in Miller, lacked standing to raise
the equal protection rights of his father. Id., at 445 (O’Con-
nor, J., joined by Kennedy, J., concurring in judgment).
Since Miller, the Courts of Appeal have divided over the
constitutionality of § 1409. Compare 208 F. 3d 528 (CA5
2000) (case below) with Lake v. Reno, 226 F. 3d 141 (CA2
2000), and United States v. Ahumada-Aguilar, 189 F. 3d 1121
(CA9 1999). We granted certiorari to resolve the conflict.
530 U. S. 1305 (2000). The father is before the Court in
this case; and, as all agree he has standing to raise the con-
stitutional claim, we now resolve it. We hold that § 1409(a)

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is consistent with the constitutional guarantee of equal
protection.
II
The general requirement for acquisition of citizenship
by a child born outside the United States and its outlying
possessions and to parents who are married, one of whom
is a citizen and the other of whom is an alien, is set forth
in 8 U. S. C. § 1401(g). The statute provides that the child
is also a citizen if, before the birth, the citizen parent had
been physically present in the United States for a total of
five years, at least two of which were after the parent turned
14 years of age.
As to an individual born under the same circumstances,
save that the parents are unwed, § 1409(a) sets forth the fol-
lowing requirements where the father is the citizen parent
and the mother is an alien:
“(1) a blood relationship between the person and the
father is established by clear and convincing evidence,
“(2) the father had the nationality of the United
States at the time of the person’s birth,
“(3) the father (unless deceased) has agreed in writing
to provide financial support for the person until the per-
son reaches the age of 18 years, and
“(4) while the person is under the age of 18 years—
“(A) the person is legitimated under the law of the
person’s residence or domicile,
“(B) the father acknowledges paternity of the person
in writing under oath, or
“(C) the paternity of the person is established by ad-
judication of a competent court.”
In addition, § 1409(a) incorporates by reference, as to the
citizen parent, the residency requirement of § 1401(g).
When the citizen parent of the child born abroad and out
of wedlock is the child’s mother, the requirements for the
transmittal of citizenship are described in § 1409(c):

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“(c) Notwithstanding the provision of subsection (a)
of this section, a person born, after December 23, 1952,
outside the United States and out of wedlock shall be
held to have acquired at birth the nationality status of
his mother, if the mother had the nationality of the
United States at the time of such person’s birth, and if
the mother had previously been physically present in
the United States or one of its outlying possessions for
a continuous period of one year.”
Section 1409(a) thus imposes a set of requirements on the
children of citizen fathers born abroad and out of wedlock
to a noncitizen mother that are not imposed under like
circumstances when the citizen parent is the mother. All
concede the requirements of §§ 1409(a)(3) and (a)(4), relat-
ing to a citizen father’s acknowledgment of a child while
he is under 18, were not satisfied in this case. We need not
discuss § 1409(a)(3), however. It was added in 1986, after
Nguyen’s birth; and Nguyen falls within a transitional rule
which allows him to elect application of either the cur-
rent version of the statute, or the pre-1986 version, which
contained no parallel to § 1409(a)(3). See Immigration and
Nationality Act Amendments of 1986, 100 Stat. 3655; note
following 8 U. S. C. § 1409; Miller, supra, at 426, n. 3, 432
(opinion of Stevens, J.). And in any event, our ruling re-
specting § 1409(a)(4) is dispositive of the case. As an in-
dividual seeking citizenship under § 1409(a) must meet all
of its preconditions, the failure to satisfy § 1409(a)(4) renders
Nguyen ineligible for citizenship.
III
For a gender-based classification to withstand equal pro-
tection scrutiny, it must be established “ ‘at least that the
[challenged] classification serves “important governmental
objectives and that the discriminatory means employed”
are “substantially related to the achievement of those ob-
jectives.” ’ ” United States v. Virginia, 518 U. S. 515, 533

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(1996) (quoting Mississippi Univ. for Women v. Hogan, 458
U. S. 718, 724 (1982), in turn quoting Wengler v. Druggists
Mut. Ins. Co., 446 U. S. 142, 150 (1980)). For reasons to
follow, we conclude § 1409 satisfies this standard. Given
that determination, we need not decide whether some lesser
degree of scrutiny pertains because the statute impli-
cates Congress’ immigration and naturalization power. See
Miller, 523 U. S., at 434, n. 11 (explaining that the statute
must be subjected to a standard more deferential to the
congressional exercise of the immigration and naturalization
power, but that “[e]ven if . . . the heightened scrutiny that
normally governs gender discrimination claims applied in
this context,” the statute would be sustained (citations
omitted)).
Before considering the important governmental inter-
ests advanced by the statute, two observations concerning
the operation of the provision are in order. First, a citizen
mother expecting a child and living abroad has the right to
reenter the United States so the child can be born here
and be a 14th Amendment citizen. From one perspective,
then, the statute simply ensures equivalence between two
expectant mothers who are citizens abroad if one chooses
to reenter for the child’s birth and the other chooses not to
return, or does not have the means to do so. This equiva-
lence is not a factor if the single citizen parent living abroad
is the father. For, unlike the unmarried mother, the un-
married father as a general rule cannot control where the
child will be born.
Second, although § 1409(a)(4) requires certain conduct to
occur before the child of a citizen father, born out of wedlock
and abroad, reaches 18 years of age, it imposes no limitations
on when an individual who qualifies under the statute can
claim citizenship. The statutory treatment of citizenship is
identical in this respect whether the citizen parent is the
mother or the father. A person born to a citizen parent of
either gender may assert citizenship, assuming compliance

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with statutory preconditions, regardless of his or her age.
And while the conditions necessary for a citizen mother
to transmit citizenship under § 1409(c) exist at birth, citi-
zen fathers and/or their children have 18 years to satisfy
the requirements of § 1409(a)(4). See Miller, supra, at 435
(opinion of Stevens, J.).
The statutory distinction relevant in this case, then, is
that § 1409(a)(4) requires one of three affirmative steps to
be taken if the citizen parent is the father, but not if the
citizen parent is the mother: legitimation; a declaration of
paternity under oath by the father; or a court order of pa-
ternity. Congress’ decision to impose requirements on un-
married fathers that differ from those on unmarried mothers
is based on the significant difference between their respec-
tive relationships to the potential citizen at the time of birth.
Specifically, the imposition of the requirement for a paternal
relationship, but not a maternal one, is justified by two im-
portant governmental objectives. We discuss each in turn.
A
The first governmental interest to be served is the im-
portance of assuring that a biological parent-child rela-
tionship exists. In the case of the mother, the relation is
verifiable from the birth itself. The mother’s status is docu-
mented in most instances by the birth certificate or hospital
records and the witnesses who attest to her having given
birth.
In the case of the father, the uncontestable fact is that
he need not be present at the birth. If he is present, fur-
thermore, that circumstance is not incontrovertible proof
of fatherhood. See Lehr v. Robertson, 463 U. S. 248, 260,
n. 16 (1983) (“ ‘The mother carries and bears the child, and
in this sense her parental relationship is clear. The validity
of the father’s parental claims must be gauged by other
measures’ ” (quoting Caban v. Mohammed, 441 U. S. 380, 397
(1979) (Stewart, J., dissenting))); Trimble v. Gordon, 430

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U. S. 762, 770 (1977) (“The more serious problems of prov-
ing paternity might justify a more demanding standard for
illegitimate children claiming under their fathers’ estates
than that required . . . under their mothers’ estates . . .”).
Fathers and mothers are not similarly situated with re-
gard to the proof of biological parenthood. The imposition
of a different set of rules for making that legal determi-
nation with respect to fathers and mothers is neither sur-
prising nor troublesome from a constitutional perspective.
Cf. Cleburne v. Cleburne Living Center, Inc., 473 U. S. 432,
439 (1985) (explaining that the Equal Protection Clause
“is essentially a direction that all persons similarly situated
should be treated alike”); F. S. Royster Guano Co. v. Vir-
ginia, 253 U. S. 412, 415 (1920). Section 1409(a)(4)’s pro-
vision of three options for a father seeking to establish
paternity—legitimation, paternity oath, and court order of
paternity—is designed to ensure an acceptable documenta-
tion of paternity.
Petitioners argue that the requirement of § 1409(a)(1), that
a father provide clear and convincing evidence of parentage,
is sufficient to achieve the end of establishing paternity,
given the sophistication of modern DNA tests. Brief for
Petitioners 21–24. Section 1409(a)(1) does not actually man-
date a DNA test, however. The Constitution, moreover,
does not require that Congress elect one particular mecha-
nism from among many possible methods of establishing
paternity, even if that mechanism arguably might be the
most scientifically advanced method. With respect to DNA
testing, the expense, reliability, and availability of such test-
ing in various parts of the world may have been of particular
concern to Congress. See Miller, supra, at 437 (opinion of
Stevens, J.). The requirement of § 1409(a)(4) represents a
reasonable conclusion by the legislature that the satisfac-
tion of one of several alternatives will suffice to establish
the blood link between father and child required as a predi-
cate to the child’s acquisition of citizenship. Cf. Lehr, supra,

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at 267–268 (upholding New York statutory requirement that
gave mothers of children born out of wedlock notice of an
adoption hearing, but only extended that right to fathers
who mailed a postcard to a “putative fathers registry”).
Given the proof of motherhood that is inherent in birth itself,
it is unremarkable that Congress did not require the same
affirmative steps of mothers.
Finally, to require Congress to speak without reference
to the gender of the parent with regard to its objective of
ensuring a blood tie between parent and child would be to
insist on a hollow neutrality. As Justice Stevens pointed
out in Miller, Congress could have required both mothers
and fathers to prove parenthood within 30 days or, for that
matter, 18 years, of the child’s birth. 523 U. S., at 436.
Given that the mother is always present at birth, but that
the father need not be, the facially neutral rule would some-
times require fathers to take additional affirmative steps
which would not be required of mothers, whose names will
appear on the birth certificate as a result of their presence
at the birth, and who will have the benefit of witnesses to
the birth to call upon. The issue is not the use of gender
specific terms instead of neutral ones. Just as neutral terms
can mask discrimination that is unlawful, gender specific
terms can mark a permissible distinction. The equal protec-
tion question is whether the distinction is lawful. Here, the
use of gender specific terms takes into account a biological
difference between the parents. The differential treatment
is inherent in a sensible statutory scheme, given the unique
relationship of the mother to the event of birth.
B
1
The second important governmental interest furthered
in a substantial manner by § 1409(a)(4) is the determination
to ensure that the child and the citizen parent have some
demonstrated opportunity or potential to develop not just a

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relationship that is recognized, as a formal matter, by the
law, but one that consists of the real, everyday ties that
provide a connection between child and citizen parent and,
in turn, the United States. See id., at 438–440 (opinion of
Stevens, J.). In the case of a citizen mother and a child
born overseas, the opportunity for a meaningful relationship
between citizen parent and child inheres in the very event
of birth, an event so often critical to our constitutional and
statutory understandings of citizenship. The mother knows
that the child is in being and is hers and has an initial point
of contact with him. There is at least an opportunity for
mother and child to develop a real, meaningful relationship.
The same opportunity does not result from the event of
birth, as a matter of biological inevitability, in the case of the
unwed father. Given the 9-month interval between con-
ception and birth, it is not always certain that a father will
know that a child was conceived, nor is it always clear that
even the mother will be sure of the father’s identity. This
fact takes on particular significance in the case of a child
born overseas and out of wedlock. One concern in this con-
text has always been with young people, men for the most
part, who are on duty with the Armed Forces in foreign
countries. See Department of Defense, Selected Manpower
Statistics 48, 74 (1999) (reporting that in 1969, the year in
which Nguyen was born, there were 3,458,072 active duty
military personnel, 39,506 of whom were female); Depart-
ment of Defense, Selected Manpower Statistics 29 (1970)
(noting that 1,041,094 military personnel were stationed in
foreign countries in 1969); Department of Defense, Selected
Manpower Statistics 49, 76 (1999) (reporting that in 1999
there were 1,385,703 active duty military personnel, 200,287
of whom were female); id., at 33 (noting that 252,763 military
personnel were stationed in foreign countries in 1999).
When we turn to the conditions which prevail today, we
find that the passage of time has produced additional and
even more substantial grounds to justify the statutory dis-

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tinction. The ease of travel and the willingness of Ameri-
cans to visit foreign countries have resulted in numbers
of trips abroad that must be of real concern when we con-
template the prospect of accepting petitioners’ argument,
which would mandate, contrary to Congress’ wishes, citizen-
ship by male parentage subject to no condition save the
father’s previous length of residence in this country. In
1999 alone, Americans made almost 25 million trips abroad,
excluding trips to Canada and Mexico. See U. S. Dept. of
Commerce, 1999 Profile of U. S. Travelers to Overseas Des-
tinations 1 (Oct. 2000). Visits to Canada and Mexico add
to this figure almost 34 million additional visits. See U. S.
Dept. of Commerce, U. S. Resident Travel to Overseas Coun-
tries, Historical Visitation 1989–1999, p. 1 (Oct. 2000). And
the average American overseas traveler spent 15.1 nights
out of the United States in 1999. 1999 Profile of U. S. Trav-
elers to Overseas Destinations, supra, at 4.
Principles of equal protection do not require Congress to
ignore this reality. To the contrary, these facts demonstrate
the critical importance of the Government’s interest in en-
suring some opportunity for a tie between citizen father
and foreign born child which is a reasonable substitute for
the opportunity manifest between mother and child at the
time of birth. Indeed, especially in light of the number of
Americans who take short sojourns abroad, the prospect
that a father might not even know of the conception is a
realistic possibility. See Miller, supra, at 439 (opinion of
Stevens, J.). Even if a father knows of the fact of concep-
tion, moreover, it does not follow that he will be present at
the birth of the child. Thus, unlike the case of the mother,
there is no assurance that the father and his biological child
will ever meet. Without an initial point of contact with the
child by a father who knows the child is his own, there is
no opportunity for father and child to begin a relationship.
Section 1409 takes the unremarkable step of ensuring that
such an opportunity, inherent in the event of birth as to the

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mother-child relationship, exists between father and child
before citizenship is conferred upon the latter.
The importance of the governmental interest at issue here
is too profound to be satisfied merely by conducting a DNA
test. The fact of paternity can be established even without
the father’s knowledge, not to say his presence. Paternity
can be established by taking DNA samples even from a
few strands of hair, years after the birth. See Federal Ju-
dicial Center, Reference Manual on Scientific Evidence 497
(2d ed. 2000). Yet scientific proof of biological paternity
does nothing, by itself, to ensure contact between father and
child during the child’s minority.
Congress is well within its authority in refusing, absent
proof of at least the opportunity for the development of a
relationship between citizen parent and child, to commit this
country to embracing a child as a citizen entitled as of birth
to the full protection of the United States, to the absolute
right to enter its borders, and to full participation in the
political process. If citizenship is to be conferred by the un-
witting means petitioners urge, so that its acquisition abroad
bears little relation to the realities of the child’s own ties and
allegiances, it is for Congress, not this Court, to make that
determination. Congress has not taken that path but has
instead chosen, by means of § 1409, to ensure in the case of
father and child the opportunity for a relationship to develop,
an opportunity which the event of birth itself provides for
the mother and child. It should be unobjectionable for Con-
gress to require some evidence of a minimal opportunity for
the development of a relationship with the child in terms the
male can fulfill.
While the INS’ brief contains statements indicating the
governmental interest we here describe, see Brief for Re-
spondent 38, 41, it suggests other interests as well. State-
ments from the INS’ brief are not conclusive as to the objects
of the statute, however, as we are concerned with the objec-
tives of Congress, not those of the INS. We ascertain the

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purpose of a statute by drawing logical conclusions from its
text, structure, and operation.
Petitioners and their amici argue in addition that, rather
than fulfilling an important governmental interest, § 1409
merely embodies a gender-based stereotype. Although the
above discussion should illustrate that, contrary to petition-
ers’ assertions, § 1409 addresses an undeniable difference in
the circumstance of the parents at the time a child is born,
it should be noted, furthermore, that the difference does not
result from some stereotype, defined as a frame of mind re-
sulting from irrational or uncritical analysis. There is noth-
ing irrational or improper in the recognition that at the mo-
ment of birth—a critical event in the statutory scheme and
in the whole tradition of citizenship law—the mother’s
knowledge of the child and the fact of parenthood have been
established in a way not guaranteed in the case of the unwed
father. This is not a stereotype. See Virginia, 518 U. S.,
at 533 (“The heightened review standard our precedent
establishes does not make sex a proscribed classifica-
tion. . . . Physical differences between men and women . . .
are enduring”).
2
Having concluded that facilitation of a relationship be-
tween parent and child is an important governmental in-
terest, the question remains whether the means Congress
chose to further its objective—the imposition of certain ad-
ditional requirements upon an unwed father—substantially
relate to that end. Under this test, the means Congress
adopted must be sustained.
First, it should be unsurprising that Congress decided
to require that an opportunity for a parent-child relation-
ship occur during the formative years of the child’s minority.
In furtherance of the desire to ensure some tie between this
country and one who seeks citizenship, various other statu-
tory provisions concerning citizenship and naturalization
require some act linking the child to the United States to

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occur before the child reaches 18 years of age. See, e. g., 8
U. S. C. § 1431 (child born abroad to one citizen parent and
one noncitizen parent shall become a citizen if, inter alia, the
noncitizen parent is naturalized before the child reaches 18
years of age and the child begins to reside in the United
States before he or she turns 18); § 1432 (imposing same con-
ditions in the case of a child born abroad to two alien parents
who are naturalized).
Second, petitioners argue that § 1409(a)(4) is not effective.
In particular, petitioners assert that, although a mother will
know of her child’s birth, “knowledge that one is a parent,
no matter how it is acquired, does not guarantee a rela-
tionship with one’s child.” Brief for Petitioners 16. They
thus maintain that the imposition of the additional require-
ments of § 1409(a)(4) only on the children of citizen fathers
must reflect a stereotype that women are more likely than
men to actually establish a relationship with their children.
Id., at 17.
This line of argument misconceives the nature of both the
governmental interest at issue and the manner in which we
examine statutes alleged to violate equal protection. As to
the former, Congress would of course be entitled to advance
the interest of ensuring an actual, meaningful relationship
in every case before citizenship is conferred. Or Congress
could excuse compliance with the formal requirements when
an actual father-child relationship is proved. It did neither
here, perhaps because of the subjectivity, intrusiveness, and
difficulties of proof that might attend an inquiry into any
particular bond or tie. Instead, Congress enacted an easily
administered scheme to promote the different but still
substantial interest of ensuring at least an opportunity for
a parent-child relationship to develop. Petitioners’ argu-
ment confuses the means and ends of the equal protection
inquiry; § 1409(a)(4) should not be invalidated because Con-
gress elected to advance an interest that is less demanding
to satisfy than some other alternative.

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Even if one conceives of the interest Congress pursues
as the establishment of a real, practical relationship of con-
siderable substance between parent and child in every case,
as opposed simply to ensuring the potential for the rela-
tionship to begin, petitioners’ misconception of the nature
of the equal protection inquiry is fatal to their argument.
A statute meets the equal protection standard we here apply
so long as it is “ ‘ “substantially related to the achievement
of ” ’ ” the governmental objective in question. Virginia,
supra, at 533 (quoting Hogan, 458 U. S., at 724, in turn quot-
ing Wengler, 446 U. S., at 150). It is almost axiomatic that
a policy which seeks to foster the opportunity for meaningful
parent-child bonds to develop has a close and substantial
bearing on the governmental interest in the actual forma-
tion of that bond. None of our gender-based classification
equal protection cases have required that the statute under
consideration must be capable of achieving its ultimate ob-
jective in every instance. In this difficult context of con-
ferring citizenship on vast numbers of persons, the means
adopted by Congress are in substantial furtherance of impor-
tant governmental objectives. The fit between the means
and the important end is “exceedingly persuasive.” See
Virginia, supra, at 533. We have explained that an “ex-
ceedingly persuasive justification” is established “by show-
ing at least that the classification serves ‘important gov-
ernmental objectives and that the discriminatory means
employed’ are ‘substantially related to the achievement of
those objectives.’ ” Hogan, supra, at 724 (citations omitted).
Section 1409 meets this standard.
C
In analyzing § 1409(a)(4), we are mindful that the obli-
gation it imposes with respect to the acquisition of citizen-
ship by the child of a citizen father is minimal. This circum-
stance shows that Congress has not erected inordinate and
unnecessary hurdles to the conferral of citizenship on the

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children of citizen fathers in furthering its important objec-
tives. Only the least onerous of the three options provided
for in § 1409(a)(4) must be satisfied. If the child has been
legitimated under the law of the relevant jurisdiction, that
will be the end of the matter. See § 1409(a)(4)(A). In the
alternative, a father who has not legitimated his child by
formal means need only make a written acknowledgment
of paternity under oath in order to transmit citizenship to
his child, hardly a substantial burden. See § 1409(a)(4)(B).
Or, the father could choose to obtain a court order of pa-
ternity. See § 1409(a)(4)(C). The statute can be satisfied on
the day of birth, or the next day, or for the next 18 years.
In this case, the unfortunate, even tragic, circumstance is
that Boulais did not pursue, or perhaps did not know of, these
simple steps and alternatives. Any omission, however, does
not nullify the statutory scheme.
Section 1409(a), moreover, is not the sole means by which
the child of a citizen father can attain citizenship. An indi-
vidual who fails to comply with § 1409(a), but who has sub-
stantial ties to the United States, can seek citizenship in his
or her own right, rather than via reliance on ties to a citizen
parent. See, e. g., 8 U. S. C. §§ 1423, 1427. This option now
may be foreclosed to Nguyen, but any bar is due to the seri-
ous nature of his criminal offenses, not to an equal protec-
tion denial or to any supposed rigidity or harshness in the
citizenship laws.
IV
The statutory scheme’s satisfaction of the equal protec-
tion scrutiny we apply to gender-based classifications consti-
tutes a sufficient basis for upholding it. It should be noted,
however, that, even were we to conclude that the statute
did not meet this standard of review, petitioners would face
additional obstacles before they could prevail.
The INS urges that, irrespective of whether § 1409(a) is
constitutional, the Court cannot grant the relief petitioners
request: the conferral of citizenship on terms other than

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those specified by Congress. There may well be “potential
problems with fashioning a remedy” were we to find the
statute unconstitutional. See Miller, 523 U. S., at 451
(O’Connor, J., concurring in judgment); cf. id., at 445, n. 26
(opinion of Stevens, J.) (declining to address the question
whether the Court could confer the sought-after remedy).
Two Members of today’s majority said in Miller that this
argument was dispositive. See id., at 452–459 (Scalia, J.,
joined by Thomas, J., concurring in judgment). Petitioners
ask us to invalidate and sever §§ 1409(a)(3) and (a)(4), but
it must be remembered that severance is based on the
assumption that Congress would have intended the result.
See id., at 457 (Scalia, J., concurring in judgment) (citing
New York v. United States, 505 U. S. 144 (1992)). In this
regard, it is significant that, although the Immigration and
Nationality Act contains a general severability provision,
Congress expressly provided with respect to the very sub-
chapter of the United States Code at issue and in a provi-
sion entitled “Sole procedure” that “[a] person may only be
naturalized as a citizen of the United States in the manner
and under the conditions prescribed in this subchapter and
not otherwise.” 8 U. S. C. § 1421(d); see also Miller, supra,
at 457–458 (Scalia, J., concurring in judgment). Section
1421(d) refers to naturalization, which in turn is defined as
“conferring of nationality of a state upon a person after
birth.” 8 U. S. C. § 1101(a)(23). Citizenship under § 1409(a)
is retroactive to the date of birth, but it is a naturalization
under § 1421(d) nevertheless. The conditions specified by
§ 1409(a) for conferral of citizenship, as a matter of definition,
must take place after the child is born, in some instances
taking as long as 18 years. Section 1409(a), then, is subject
to the limitation imposed by § 1421(d).
In light of our holding that there is no equal protection
violation, we need not rely on this argument. For the same
reason, we need not assess the implications of statements in
our earlier cases regarding the wide deference afforded to

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Congress in the exercise of its immigration and naturaliza-
tion power. See, e. g., Fiallo v. Bell, 430 U. S. 787, 792–793,
and n. 4 (1977) (quoting Galvan v. Press, 347 U. S. 522, 531
(1954)); 430 U. S., at 792 (quoting Oceanic Steam Nav. Co. v.
Stranahan, 214 U. S. 320, 339 (1909)). These arguments
would have to be considered, however, were it to be de-
termined that § 1409 did not withstand conventional equal
protection scrutiny.
V
To fail to acknowledge even our most basic biological
differences—such as the fact that a mother must be pres-
ent at birth but the father need not be—risks making the
guarantee of equal protection superficial, and so disserv-
ing it. Mechanistic classification of all our differences as
stereotypes would operate to obscure those misconceptions
and prejudices that are real. The distinction embodied in
the statutory scheme here at issue is not marked by mis-
conception and prejudice, nor does it show disrespect for
either class. The difference between men and women in re-
lation to the birth process is a real one, and the principle
of equal protection does not forbid Congress to address the
problem at hand in a manner specific to each gender.
The judgment of the Court of Appeals is
Affirmed.
Justice Scalia, with whom Justice Thomas joins,
concurring.
I remain of the view that the Court lacks power to pro-
vide relief of the sort requested in this suit—namely, con-
ferral of citizenship on a basis other than that prescribed by
Congress. See Miller v. Albright, 523 U. S. 420, 452 (1998)
(Scalia, J., concurring in judgment). A majority of the
Justices in Miller having concluded otherwise, see id., at
423 (opinion of Stevens, J., joined by Rehnquist, C. J.);
id., at 460 (Ginsburg, J., joined by Souter and Breyer, JJ.,
dissenting); id., at 471 (Breyer, J., joined by Souter and

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74 TUAN ANH NGUYEN v. INS
O’Connor, J., dissenting
Ginsburg, JJ., dissenting); and a majority of the Court today
proceeding on the same assumption; I think it appropriate
for me to reach the merits of petitioners’ equal protection
claims. I join the opinion of the Court.
Justice O’Connor, with whom Justice Souter, Justice
Ginsburg, and Justice Breyer join, dissenting.
In a long line of cases spanning nearly three decades, this
Court has applied heightened scrutiny to legislative classifi-
cations based on sex. The Court today confronts another
statute that classifies individuals on the basis of their sex.
While the Court invokes heightened scrutiny, the manner in
which it explains and applies this standard is a stranger
to our precedents. Because the Immigration and Natural-
ization Service (INS) has not shown an exceedingly persua-
sive justification for the sex-based classification embodied in
8 U. S. C. § 1409(a)(4)—i. e., because it has failed to establish
at least that the classification substantially relates to the
achievement of important governmental objectives—I would
reverse the judgment of the Court of Appeals.
I
Sex-based statutes, even when accurately reflecting the
way most men or women behave, deny individuals opportu-
nity. Such generalizations must be viewed not in isolation,
but in the context of our Nation’s “ ‘long and unfortunate
history of sex discrimination.’ ” J. E. B. v. Alabama ex rel.
T. B., 511 U. S. 127, 136 (1994) (quoting Frontiero v. Richard-
son, 411 U. S. 677, 684 (1973) (plurality opinion)). Sex-based
generalizations both reflect and reinforce “fixed notions con-
cerning the roles and abilities of males and females.” Mis-
sissippi Univ. for Women v. Hogan, 458 U. S. 718, 725 (1982).
For these reasons, a party who seeks to defend a statute
that classifies individuals on the basis of sex “must carry the
burden of showing an ‘exceedingly persuasive justification’
for the classification.” Id., at 724 (quoting Kirchberg v.

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75 Cite as: 533 U. S. 53 (2001)
O’Connor, J., dissenting
Feenstra, 450 U. S. 455, 461 (1981)); see also United States
v. Virginia, 518 U. S. 515, 531 (1996). The defender of the
classification meets this burden “only by showing at least
that the classification serves ‘important governmental ob-
jectives and that the discriminatory means employed’ are
‘substantially related to the achievement of those objec-
tives.’ ” Mississippi Univ. for Women, supra, at 724 (quot-
ing Wengler v. Druggists Mut. Ins. Co., 446 U. S. 142, 150
(1980)); see also Virginia, 518 U. S., at 533.
Our cases provide significant guidance concerning the
meaning of this standard and how a reviewing court is to
apply it. This Court’s instruction concerning the application
of heightened scrutiny to sex-based classifications stands in
stark contrast to our elucidation of the rudiments of rational
basis review. To begin with, under heightened scrutiny,
“[t]he burden of justification is demanding and it rests en-
tirely on [the party defending the classification].” Ibid.
Under rational basis scrutiny, by contrast, the defender of
the classification “has no obligation to produce evidence to
sustain the rationality of a statutory classification.” Heller
v. Doe, 509 U. S. 312, 320 (1993). Instead, “[t]he burden is
on the one attacking the legislative arrangement to negative
every conceivable basis which might support it, whether or
not the basis has a foundation in the record.” Id., at 320–
321 (internal quotation marks and citation omitted).
Further, a justification that sustains a sex-based clas-
sification “must be genuine, not hypothesized or invented
post hoc in response to litigation.” Virginia, supra, at 533.
“[T]he mere recitation of a benign, compensatory purpose is
not an automatic shield which protects against any inquiry
into the actual purposes underlying a statutory scheme.”
Weinberger v. Wiesenfeld, 420 U. S. 636, 648 (1975). Under
rational basis review, by contrast, it is “ ‘constitutionally
irrelevant [what] reasoning in fact underlay the legislative
decision.’ ” Railroad Retirement Bd. v. Fritz, 449 U. S. 166,

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76 TUAN ANH NGUYEN v. INS
O’Connor, J., dissenting
179 (1980) (quoting Flemming v. Nestor, 363 U. S. 603, 612
(1960)).
Heightened scrutiny does not countenance justifications
that “rely on overbroad generalizations about the differ-
ent talents, capacities, or preferences of males and females.”
Virginia, supra, at 533. Rational basis review, by con-
trast, is much more tolerant of the use of broad general-
izations about different classes of individuals, so long as the
classification is not arbitrary or irrational. See, e. g., Kimel
v. Florida Bd. of Regents, 528 U. S. 62, 84 (2000); Fritz,
supra, at 177.
Moreover, overbroad sex-based generalizations are imper-
missible even when they enjoy empirical support. See, e. g.,
J. E. B., supra, at 139, n. 11; Craig v. Boren, 429 U. S. 190,
199 (1976); Wiesenfeld, supra, at 645. Under rational basis
scrutiny, however, empirical support is not even necessary
to sustain a classification. See, e. g., FCC v. Beach Com-
munications, Inc., 508 U. S. 307, 315 (1993) (“[A] legislative
choice is not subject to courtroom factfinding and may be
based on rational speculation unsupported by evidence or
empirical data”).
The different burdens imposed by these equal protection
standards correspond to the different duties of a reviewing
court in applying each standard. The court’s task in apply-
ing heightened scrutiny to a sex-based classification is clear:
“Focusing on the differential treatment or denial of opportu-
nity for which relief is sought, the reviewing court must de-
termine whether the proffered justification is ‘exceedingly
persuasive.’ ” Virginia, 518 U. S., at 532–533. In making
this determination, the court must inquire into the actual
purposes of the discrimination, for “a tenable justification
must describe actual state purposes, not rationalizations
for actions in fact differently grounded.” Id., at 535–536;
see also id., at 533; Wiesenfeld, supra, at 648; Califano v.
Goldfarb, 430 U. S. 199, 212–217 (1977) (plurality opinion);
id., at 219–221 (Stevens, J., concurring in judgment). The

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rational basis standard, on the other hand, instructs that
“a classification ‘must be upheld against equal protection
challenge if there is any reasonably conceivable state of
facts that could provide a rational basis for the classifi-
cation.’ ” Heller, supra, at 320 (quoting Beach Communi-
cations, supra, at 313). This standard permits a court to
hypothesize interests that might support legislative dis-
tinctions, whereas heightened scrutiny limits the realm of
justification to demonstrable reality.
These different standards of equal protection review also
set different bars for the magnitude of the governmental in-
terest that justifies the statutory classification. Heightened
scrutiny demands that the governmental interest served by
the classification be “important,” see, e. g., Virginia, supra,
at 533, whereas rational basis scrutiny requires only that the
end be “legitimate,” see, e. g., Nordlinger v. Hahn, 505 U. S.
1, 10 (1992).
The most important difference between heightened scru-
tiny and rational basis review, of course, is the required fit
between the means employed and the ends served. Under
heightened scrutiny, the discriminatory means must be
“substantially related” to an actual and important govern-
mental interest. See, e. g., Virginia, supra, at 533. Under
rational basis scrutiny, the means need only be “rationally
related” to a conceivable and legitimate state end. See, e. g.,
Cleburne v. Cleburne Living Center, Inc., 473 U. S. 432, 440
(1985).
The fact that other means are better suited to the achieve-
ment of governmental ends therefore is of no moment under
rational basis review. See, e. g., Vance v. Bradley, 440 U. S.
93, 103, n. 20 (1979) (“Even were it not irrelevant to [rational
basis review] that other alternatives might achieve approxi-
mately the same results . . .”); Massachusetts Bd. of Re-
tirement v. Murgia, 427 U. S. 307, 316 (1976) (per curiam)
(“[T]he State perhaps has not chosen the best means to ac-
complish this purpose. But where rationality is the test, a

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78 TUAN ANH NGUYEN v. INS
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State ‘does not violate the Equal Protection Clause merely
because the classifications made by its laws are imperfect’ ”
(quoting Dandridge v. Williams, 397 U. S. 471, 485 (1970))).
But because we require a much tighter fit between means
and ends under heightened scrutiny, the availability of
sex-neutral alternatives to a sex-based classification is often
highly probative of the validity of the classification. See,
e. g., Wengler, 446 U. S., at 151 (invalidating a sex-based
classification where a sex-neutral approach would com-
pletely serve the needs of both classes); Orr v. Orr, 440 U. S.
268, 281 (1979) (finding “no reason, therefore, to use sex as a
proxy for need” where the alimony statute already pro-
vided for individualized hearings that took financial circum-
stances into account); Wiesenfeld, 420 U. S., at 653 (finding
a gender-based distinction to be “gratuitous” where “with-
out it, the statutory scheme would only provide benefits to
those men who are in fact similarly situated to the women
the statute aids”).
II
The Court recites the governing substantive standard for
heightened scrutiny of sex-based classifications, see ante, at
60–61, 70, but departs from the guidance of our precedents
concerning such classifications in several ways. In the first
sentence of its equal protection analysis, the majority glosses
over the crucial matter of the burden of justification. Ante,
at 60 (“For a gender-based classification to withstand equal
protection scrutiny, it must be established . . .”); see also
ante, at 70. In other circumstances, the Court’s use of an
impersonal construction might represent a mere elision of
what we have stated expressly in our prior cases. Here,
however, the elision presages some of the larger failings of
the opinion.
For example, the majority hypothesizes about the in-
terests served by the statute and fails adequately to in-
quire into the actual purposes of § 1409(a)(4). The Court
also does not always explain adequately the importance

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of the interests that it claims to be served by the provi-
sion. The majority also fails carefully to consider whether
the sex-based classification is being used impermissibly “as
a ‘proxy for other, more germane bases of classification,’ ”
Mississippi Univ. for Women, 458 U. S., at 726 (quoting
Craig, 429 U. S., at 198), and instead casually dismisses the
relevance of available sex-neutral alternatives. And, con-
trary to the majority’s conclusion, the fit between the means
and ends of § 1409(a)(4) is far too attenuated for the provision
to survive heightened scrutiny. In all, the majority opinion
represents far less than the rigorous application of height-
ened scrutiny that our precedents require.
A
According to the Court, “[t]he first governmental interest
to be served is the importance of assuring that a biological
parent-child relationship exists.” Ante, at 62. The major-
ity does not elaborate on the importance of this interest,
which presumably lies in preventing fraudulent conveyances
of citizenship. Nor does the majority demonstrate that this
is one of the actual purposes of § 1409(a)(4). Assuming that
Congress actually had this purpose in mind in enacting parts
of § 1409(a)(4), cf. Miller v. Albright, 523 U. S. 420, 435–436
(1998) (opinion of Stevens, J.), the INS does not appear to
rely on this interest in its effort to sustain § 1409(a)(4)’s sex-
based classification. Cf. Brief for Respondent 11 (claiming
that § 1409 serves “at least two important interests: first,
ensuring that children who are born abroad out of wedlock
have, during their minority, attained a sufficiently recog-
nized or formal relationship to their United States citizen
parent—and thus to the United States—to justify the con-
ferral of citizenship upon them; and second, preventing such
children from being stateless”). In light of the reviewing
court’s duty to “determine whether the proffered justifica-
tion is ‘exceedingly persuasive,’ ” Virginia, 518 U. S., at 533,
this disparity between the majority’s defense of the statute

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and the INS’ proffered justifications is striking, to say the
least.
The gravest defect in the Court’s reliance on this in-
terest, however, is the insufficiency of the fit between
§ 1409(a)(4)’s discriminatory means and the asserted end.
Section 1409(c) imposes no particular burden of proof on
mothers wishing to convey citizenship to their children.
By contrast, § 1409(a)(1), which petitioners do not challenge
before this Court, requires that “a blood relationship be-
tween the person and the father [be] established by clear
and convincing evidence.” Atop § 1409(a)(1), § 1409(a)(4)
requires legitimation, an acknowledgment of paternity in
writing under oath, or an adjudication of paternity before
the child reaches the age of 18. It is difficult to see what
§ 1409(a)(4) accomplishes in furtherance of “assuring that a
biological parent-child relationship exists,” ante, at 62, that
§ 1409(a)(1) does not achieve on its own. The virtual cer-
tainty of a biological link that modern DNA testing affords
reinforces the sufficiency of § 1409(a)(1). See Miller, supra,
at 484–485 (Breyer, J., dissenting).
It is also difficult to see how § 1409(a)(4)’s limitation of
the time allowed for obtaining proof of paternity substan-
tially furthers the assurance of a blood relationship. Mod-
ern DNA testing, in addition to providing accuracy un-
matched by other methods of establishing a biological link,
essentially negates the evidentiary significance of the
passage of time. Moreover, the application of § 1409(a)(1)’s
“clear and convincing evidence” requirement can account for
any effect that the passage of time has on the quality of the
evidence.
The Court criticizes petitioners’ reliance on the availabil-
ity and sophistication of modern DNA tests, ante, at 63, but
appears to misconceive the relevance of such tests. No one
argues that § 1409(a)(1) mandates a DNA test. Legitima-
tion or an adjudication of paternity, see §§ 1409(a)(4)(A), (C),
may well satisfy the “clear and convincing” standard of

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§ 1409(a)(1). (Satisfaction of § 1409(a)(4) by a written ac-
knowledgment of paternity under oath, see § 1409(a)(4)(B),
would seem to do little, if anything, to advance the assurance
of a blood relationship, further stretching the means-end
fit in this context.) Likewise, petitioners’ argument does
not depend on the idea that one particular method of es-
tablishing paternity is constitutionally required. Petition-
ers’ argument rests instead on the fact that, if the goal is to
obtain proof of paternity, the existence of a statutory pro-
vision governing such proof, coupled with the efficacy and
availability of modern technology, is highly relevant to the
sufficiency of the tailoring between § 1409(a)(4)’s sex-based
classification and the asserted end. Because § 1409(a)(4)
adds little to the work that § 1409(a)(1) does on its own, it
is difficult to say that § 1409(a)(4) “substantially furthers”
an important governmental interest. Kirchberg, 450 U. S.,
at 461.
The majority concedes that Congress could achieve the
goal of assuring a biological parent-child relationship in a
sex-neutral fashion, but then, in a surprising turn, dismisses
the availability of sex-neutral alternatives as irrelevant. As
the Court suggests, “Congress could have required both
mothers and fathers to prove parenthood within 30 days or,
for that matter, 18 years, of the child’s birth.” Ante, at 64
(citing Miller, supra, at 436 (opinion of Stevens, J.)). In-
deed, whether one conceives the majority’s asserted interest
as assuring the existence of a biological parent-child rela-
tionship, ante, at 62, or as ensuring acceptable documenta-
tion of that relationship, ante, at 63, a number of sex-neutral
arrangements—including the one that the majority offers—
would better serve that end. As the majority seems implic-
itly to acknowledge at one point, ante, at 62, a mother will
not always have formal legal documentation of birth because
a birth certificate may not issue or may subsequently be lost.
Conversely, a father’s name may well appear on a birth cer-
tificate. While it is doubtless true that a mother’s blood re-

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82 TUAN ANH NGUYEN v. INS
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lation to a child is uniquely “verifiable from the birth itself ”
to those present at birth, ibid., the majority has not shown
that a mother’s birth relation is uniquely verifiable by the
INS, much less that any greater verifiability warrants a sex-
based, rather than a sex-neutral, statute.
In our prior cases, the existence of comparable or superior
sex-neutral alternatives has been a powerful reason to reject
a sex-based classification. See supra, at 78. The majority,
however, turns this principle on its head by denigrating as
“hollow” the very neutrality that the law requires. Ante, at
64. While the majority trumpets the availability of superior
sex-neutral alternatives as confirmation of § 1409(a)(4)’s va-
lidity, our precedents demonstrate that this fact is a decided
strike against the law. Far from being “hollow,” the avoid-
ance of gratuitous sex-based distinctions is the hallmark of
equal protection. Cf. J. E. B., 511 U. S., at 152–153 (Ken-
nedy, J., concurring in judgment) (“ ‘At the heart of the Con-
stitution’s guarantee of equal protection lies the simple com-
mand that the Government must treat citizens as individuals,
not as simply components of a racial [or] sexual . . . class’ ”
(quoting Metro Broadcasting, Inc. v. FCC, 497 U. S. 547, 602
(1990) (O’Connor, J., dissenting))).
The majority’s acknowledgment of the availability of sex-
neutral alternatives scarcely confirms the point that “[t]he
differential treatment is inherent in a sensible statutory
scheme.” Ante, at 64. The discussion instead demon-
strates that, at most, differential impact will result from the
fact that “[f]athers and mothers are not similarly situated
with regard to the proof of biological parenthood.” Ante, at
63. In other words, it will likely be easier for mothers to
satisfy a sex-neutral proof of parentage requirement. But
facially neutral laws that have a disparate impact are a dif-
ferent animal for purposes of constitutional analysis than
laws that specifically provide for disparate treatment. We
have long held that the differential impact of a facially neu-
tral law does not trigger heightened scrutiny, see, e. g.,

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O’Connor, J., dissenting
Washington v. Davis, 426 U. S. 229 (1976), whereas we apply
heightened scrutiny to laws that facially classify individuals
on the basis of their sex. See, e. g., United States v. Vir-
ginia, 518 U. S. 515 (1996); see also J. E. B., supra, at 152
(Kennedy, J., concurring in judgment) (“[O]ur case law does
reveal a strong presumption that gender classifications are
invalid”); Parham v. Hughes, 441 U. S. 347, 351 (1979) (plural-
ity opinion) (“Not all legislation, however, is entitled to the
same presumption of validity. . . . [T]he presumption of statu-
tory validity may also be undermined when a State has
enacted legislation creating classes based upon certain other
immutable human attributes” (citing, inter alia, Reed v.
Reed, 404 U. S. 71 (1971))).
If rational basis scrutiny were appropriate in this case,
then the claim that “[t]he Constitution . . . does not require
that Congress elect one particular mechanism from among
many possible methods of establishing paternity,” ante, at
63, would have much greater force. So too would the claim
that “[t]he requirement of § 1409(a)(4) represents a reason-
able conclusion . . . .” Ibid. But fidelity to the Con-
stitution’s pledge of equal protection demands more when a
facially sex-based classification is at issue. This is not be-
cause we sit in judgment of the wisdom of laws in one in-
stance but not the other, cf. Beach Communications, 508
U. S., at 313, but rather because of the potential for “injury
. . . to personal dignity,” J. E. B., supra, at 153 (Kennedy, J.,
concurring in judgment), that inheres in or accompanies so
many sex-based classifications.
B
The Court states that “[t]he second important governmen-
tal interest furthered in a substantial manner by § 1409(a)(4)
is the determination to ensure that the child and the citizen
parent have some demonstrated opportunity or potential to
develop not just a relationship that is recognized, as a for-
mal matter, by the law, but one that consists of the real,

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84 TUAN ANH NGUYEN v. INS
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everyday ties that provide a connection between child and
citizen parent and, in turn, the United States.” Ante, at
64–65. The Court again fails to demonstrate that this was
Congress’ actual purpose in enacting § 1409(a)(4). The ma-
jority’s focus on “some demonstrated opportunity or poten-
tial to develop . . . real, everyday ties” in fact appears to be
the type of hypothesized rationale that is insufficient under
heightened scrutiny. See supra, at 75–77.
The INS asserts the governmental interest of “ensur-
ing that children who are born abroad out of wedlock have,
during their minority, attained a sufficiently recognized or
formal relationship to their United States citizen parent—
and thus to the United States—to justify the conferral of
citizenship upon them.” Brief for Respondent 11. The ma-
jority’s asserted end, at best, is a simultaneously watered-
down and beefed-up version of this interest asserted by the
INS. The majority’s rendition is weaker than the INS’ in
that it emphasizes the “opportunity or potential to develop”
a relationship rather than the actual relationship about
which the INS claims Congress was concerned. The majori-
ty’s version is also stronger in that it goes past the formal
relationship apparently desired by the INS to “real, every-
day ties.”
Assuming, as the majority does, that Congress was actu-
ally concerned about ensuring a “demonstrated opportunity”
for a relationship, it is questionable whether such an oppor-
tunity qualifies as an “important” governmental interest
apart from the existence of an actual relationship. By focus-
ing on “opportunity” rather than reality, the majority pre-
sumably improves the chances of a sufficient means-end fit.
But in doing so, it dilutes significantly the weight of the in-
terest. It is difficult to see how, in this citizenship-conferral
context, anyone profits from a “demonstrated opportunity”
for a relationship in the absence of the fruition of an ac-
tual tie. Children who have an “opportunity” for such a tie
with a parent, of course, may never develop an actual rela-

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85 Cite as: 533 U. S. 53 (2001)
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tionship with that parent. See Miller, 523 U. S., at 440
(opinion of Stevens, J.). If a child grows up in a foreign
country without any postbirth contact with the citizen par-
ent, then the child’s never-realized “opportunity” for a re-
lationship with the citizen seems singularly irrelevant to
the appropriateness of granting citizenship to that child.
Likewise, where there is an actual relationship, it is the
actual relationship that does all the work in rendering ap-
propriate a grant of citizenship, regardless of when and how
the opportunity for that relationship arose.
Accepting for the moment the majority’s focus on “oppor-
tunity,” the attempt to justify § 1409(a)(4) in these terms is
still deficient. Even if it is important “to require that an
opportunity for a parent-child relationship occur during
the formative years of the child’s minority,” ante, at 68,
it is difficult to see how the requirement that proof of such
opportunity be obtained before the child turns 18 substan-
tially furthers the asserted interest. As the facts of this
case demonstrate, ante, at 57, it is entirely possible that a
father and child will have the opportunity to develop a re-
lationship and in fact will develop a relationship without
obtaining the proof of the opportunity during the child’s
minority. After his parents’ relationship had ended, peti-
tioner Nguyen lived with the family of his father’s new
girlfriend. In 1975, before his sixth birthday, Nguyen came
to the United States, where he was reared by his father,
petitioner Boulais. In 1997, a DNA test showed a 99.98%
probability of paternity, and, in 1998, Boulais obtained an
order of parentage from a Texas court.
Further underscoring the gap between the discrimina-
tory means and the asserted end is the possibility that “a
child might obtain an adjudication of paternity ‘absent any
affirmative act by the father, and perhaps even over his
express objection.’ ” Miller, 523 U. S., at 486 (Breyer, J.,
dissenting) (quoting id., at 434 (opinion of Stevens, J.)).
The fact that the means-end fit can break down so readily

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in theory, and not just in practice, is hardly characteristic
of a “substantial” means-end relationship.
Moreover, available sex-neutral alternatives would at
least replicate, and could easily exceed, whatever fit there
is between § 1409(a)(4)’s discriminatory means and the ma-
jority’s asserted end. According to the Court, § 1409(a)(4) is
designed to ensure that fathers and children have the same
“opportunity which the event of birth itself provides for the
mother and child.” Ante, at 67. Even assuming that this
is so, Congress could simply substitute for § 1409(a)(4) a re-
quirement that the parent be present at birth or have knowl-
edge of birth. Cf. Miller, supra, at 487 (Breyer, J., dissent-
ing). Congress could at least allow proof of such presence
or knowledge to be one way of demonstrating an opportu-
nity for a relationship. Under the present law, the statute
on its face accords different treatment to a mother who is
by nature present at birth and a father who is by choice
present at birth even though those two individuals are
similarly situated with respect to the “opportunity” for a
relationship. The mother can transmit her citizenship at
birth, but the father cannot do so in the absence of at least
one other affirmative act. The different statutory treat-
ment is solely on account of the sex of the similarly situated
individuals. This type of treatment is patently inconsistent
with the promise of equal protection of the laws. See, e. g.,
Reed, 404 U. S., at 77 (“By providing dissimilar treatment
for men and women who are thus similarly situated, the chal-
lenged section violates the Equal Protection Clause”).
Indeed, the idea that a mother’s presence at birth sup-
plies adequate assurance of an opportunity to develop a re-
lationship while a father’s presence at birth does not would
appear to rest only on an overbroad sex-based general-
ization. A mother may not have an opportunity for a re-
lationship if the child is removed from his or her mother
on account of alleged abuse or neglect, or if the child and
mother are separated by tragedy, such as disaster or war,

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of the sort apparently present in this case. There is no rea-
son, other than stereotype, to say that fathers who are
present at birth lack an opportunity for a relationship on
similar terms. The “[p]hysical differences between men and
women,” Virginia, 518 U. S., at 533, therefore do not justify
§ 1409(a)(4)’s discrimination.
The majority later ratchets up the interest, for the sake
of argument, to “the establishment of a real, practical re-
lationship of considerable substance between parent and
child in every case, as opposed simply to ensuring the poten-
tial for the relationship to begin.” Ante, at 70. But the
majority then dismisses the distinction between opportunity
and reality as immaterial to the inquiry in this case. Ibid.
The majority rests its analysis of the means-end fit largely
on the following proposition: “It is almost axiomatic that a
policy which seeks to foster the opportunity for meaningful
parent-child bonds to develop has a close and substantial
bearing on the governmental interest in the actual formation
of that bond.” Ibid. A bare assertion of what is allegedly
“almost axiomatic,” however, is no substitute for the “de-
manding” burden of justification borne by the defender of
the classification. Virginia, supra, at 533.
Moreover, the Court’s reasoning hardly conforms to the
tailoring requirement of heightened scrutiny. The fact that
a discriminatory policy embodies the good intention of “seek-
[ing] to foster” the opportunity for something beneficial to
happen is of little relevance in itself to whether the policy
substantially furthers the desired occurrence. Whether the
classification indeed “has a close and substantial bearing”
on the actual occurrence of the preferred result depends on
facts and circumstances and must be proved by the classifi-
cation’s defender. Far from being a virtual axiom, the re-
lationship between the intent to foster an opportunity and
the fruition of the desired effect is merely a contingent
proposition. The majority’s sweeping claim is no surrogate

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for the careful application of heightened scrutiny to a par-
ticular classification.
The question that then remains is the sufficiency of the
fit between § 1409(a)(4)’s discriminatory means and the goal
of “establish[ing] . . . a real, practical relationship of con-
siderable substance.” Ante, at 70. If Congress wishes to
advance this end, it could easily do so by employing a
sex-neutral classification that is a far “more germane bas[i]s
of classification” than sex, Craig, 429 U. S., at 198. For
example, Congress could require some degree of regular
contact between the child and the citizen parent over a
period of time. See Miller, 523 U. S., at 470 (Ginsburg,
J., dissenting).
The majority again raises this possibility of the use of
sex-neutral means only to dismiss it as irrelevant. The
Court admits that “Congress could excuse compliance with
the formal requirements when an actual father-child re-
lationship is proved,” but speculates that Congress did not
do so “perhaps because of the subjectivity, intrusiveness,
and difficulties of proof that might attend an inquiry into any
particular bond or tie.” Ante, at 69. We have repeatedly
rejected efforts to justify sex-based classifications on the
ground of administrative convenience. See, e. g., Wengler,
446 U. S., at 152; Frontiero, 411 U. S., at 690–691. There is
no reason to think that this is a case where administrative
convenience concerns are so powerful that they would justify
the sex-based discrimination, cf. Wengler, supra, at 152,
especially where the use of sex as a proxy is so ill fit to the
purported ends as it is here. And to the extent Congress
might seek simply to ensure an “opportunity” for a rela-
tionship, little administrative inconvenience would seem to
accompany a sex-neutral requirement of presence at birth,
knowledge of birth, or contact between parent and child
prior to a certain age.
The claim that § 1409(a)(4) substantially relates to the
achievement of the goal of a “real, practical relationship”

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thus finds support not in biological differences but instead
in a stereotype—i. e., “the generalization that mothers are
significantly more likely than fathers . . . to develop caring
relationships with their children.” Miller, supra, at 482–
483 (Breyer, J., dissenting). Such a claim relies on “the
very stereotype the law condemns,” J. E. B., 511 U. S., at
138 (internal quotation marks omitted), “lends credibility”
to the generalization, Mississippi Univ. for Women, 458
U. S., at 730, and helps to convert that “assumption” into
“a self-fulfilling prophecy,” ibid. See also J. E. B., supra,
at 140 (“When state actors exercise peremptory challenges
in reliance on gender stereotypes, they ratify and reinforce
prejudicial views of the relative abilities of men and
women”). Indeed, contrary to this stereotype, Boulais has
reared Nguyen, while Nguyen apparently has lacked a re-
lationship with his mother.
The majority apparently tries to avoid reliance on this
stereotype by characterizing the governmental interest as a
“demonstrated opportunity” for a relationship and attempt-
ing to close the gap between opportunity and reality with a
dubious claim about what is “almost axiomatic.” But the
fact that one route is wisely forgone does not mean that
the other is plausibly taken. The inescapable conclusion in-
stead is that § 1409(a)(4) lacks an exceedingly persuasive
justification.
In denying petitioner’s claim that § 1409(a)(4) rests on
stereotypes, the majority articulates a misshapen notion of
“stereotype” and its significance in our equal protection
jurisprudence. The majority asserts that a “stereotype” is
“defined as a frame of mind resulting from irrational or
uncritical analysis.” Ante, at 68. This Court has long rec-
ognized, however, that an impermissible stereotype may
enjoy empirical support and thus be in a sense “rational.”
See, e. g., J. E. B., supra, at 139, n. 11 (“We have made abun-
dantly clear in past cases that gender classifications that rest
on impermissible stereotypes violate the Equal Protection

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Clause, even when some statistical support can be conjured
up for the generalization”); Craig, 429 U. S., at 201 (invali-
dating a sex-based classification even though the evidence
supporting the distinction was “not trivial in a statistical
sense”); id., at 202 (noting that “prior cases have consistently
rejected the use of sex as a decisionmaking factor even
though the statutes in question certainly rested on far more
predictive empirical relationships than this”); Wiesenfeld,
420 U. S., at 645 (invalidating a sex-based classification even
though the underlying generalization was “not entirely with-
out empirical support”). Indeed, the stereotypes that un-
derlie a sex-based classification “may hold true for many,
even most, individuals.” Miller, 523 U. S., at 460 (Gins-
burg, J., dissenting). But in numerous cases where a meas-
ure of truth has inhered in the generalization, “the Court
has rejected official actions that classify unnecessarily and
overbroadly by gender when more accurate and impartial
functional lines can be drawn.” Ibid.
Nor do stereotypes consist only of those overbroad gen-
eralizations that the reviewing court considers to “show
disrespect” for a class, ante, at 73. Cf., e. g., Craig, supra,
at 198–201. The hallmark of a stereotypical sex-based clas-
sification under this Court’s precedents is not whether the
classification is insulting, but whether it “relie[s] upon the
simplistic, outdated assumption that gender could be used as
a ‘proxy for other, more germane bases of classification.’ ”
Mississippi Univ. for Women, supra, at 726 (quoting Craig,
supra, at 198).
It is also important to note that, while our explanations
of many decisions invalidating sex-based classifications have
pointed to the problems of “stereotypes” and “overbroad
generalizations,” these explanations certainly do not mean
that the burden is on the challenger of the classification to
prove legislative reliance on such generalizations. Indeed,
an arbitrary distinction between the sexes may rely on no
identifiable generalization at all but may simply be a de-

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nial of opportunity out of pure caprice. Such a distinction,
of course, would nonetheless be a classic equal protection
violation. The burden of proving that use of a sex-based
classification substantially relates to the achievement of an
important governmental interest remains unmistakably and
entirely with the classification’s defender. See, e. g., Vir-
ginia, 518 U. S., at 532–533.
C
The Court has also failed even to acknowledge the “vol-
umes of history” to which “[t]oday’s skeptical scrutiny of
official action denying rights or opportunities based on sex
responds.” Id., at 531. The history of sex discrimination
in laws governing the transmission of citizenship and with
respect to parental responsibilities for children born out of
wedlock counsels at least some circumspection in discerning
legislative purposes in this context. See generally Miller,
supra, at 460–468 (Ginsburg, J., dissenting).
Section 1409 was first enacted as § 205 of the Nationality
Act of 1940, 54 Stat. 1139–1140. The 1940 Act had been
proposed by the President, forwarding a report by a spe-
cially convened Committee of Advisors, including the At-
torney General. The Committee explained to Congress the
rationale for § 205, whose sex-based classification remains in
effect today:
“[T]he Department of State has, at least since 1912,
uniformly held that an illegitimate child born abroad
of an American mother acquires at birth the national-
ity of the mother, in the absence of legitimation or ad-
judication establishing the paternity of the child. This
ruling is based . . . on the ground that the mother in
such case stands in the place of the father. . . . [U]nder
American law the mother has a right to custody and
control of such a child as against the putative father, and
is bound to maintain it as its natural guardian. This
rule seems to be in accord with the old Roman law and

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with the laws of Spain and France.” To Revise and
Codify the Nationality Laws of the United States, Hear-
ings on H. R. 6127 before the House Committee on Im-
migration and Naturalization, 76th Cong., 1st Sess., 431
(1945) (reprinting Message from the President, Nation-
ality Laws of the United States (1938)) (emphasis added
and internal quotation marks and citations omitted).
Section 1409(a)(4) is thus paradigmatic of a historic re-
gime that left women with responsibility, and freed men
from responsibility, for nonmarital children. Under this law,
as one advocate explained to Congress in a 1932 plea for a
sex-neutral citizenship law, “when it comes to the illegiti-
mate child, which is a great burden, then the mother is
the only recognized parent, and the father is put safely in
the background.” Naturalization and Citizenship Status of
Certain Children of Mothers Who Are Citizens of the United
States, Hearing on H. R. 5489 before the House Committee
on Immigration and Naturalization, 72d Cong., 1st Sess., 3
(testimony of Burnita Shelton Matthews); see also id., at 5
(citizenship law “permit[s] [the father] to escape the burdens
incident to illegitimate parenthood”). Unlike § 1409(a)(4),
our States’ child custody and support laws no longer assume
that mothers alone are “bound” to serve as “natural guard-
ians” of nonmarital children. See, e. g., Ariz. Rev. Stat. Ann.
§ 25–501 (1999) (equal duties of support); cf. Cal. Civ. Code
Ann. § 4600 (West 1972) (abolishing “tender years” doctrine).
The majority, however, rather than confronting the stereo-
typical notion that mothers must care for these children and
fathers may ignore them, quietly condones the “very stereo-
type the law condemns,” J. E. B., 511 U. S., at 138 (internal
quotation marks omitted).
Punctuating the disparity between the majority’s and the
INS’ accounts of the governmental interests at stake is the
majority’s failure even to address the INS’ second asserted
rationale: that § 1409 prevents certain children from being
stateless. Brief for Respondent 11; see also id., at 17–18

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O’Connor, J., dissenting
(describing statelessness problem). The Court certainly has
good reason to reject this asserted rationale. Indeed, the
INS hardly even attempts to show how the statelessness
concern justifies the discriminatory means of § 1409(a)(4) in
particular. The INS instead undertakes a demonstration
of how the statelessness concern justifies § 1409(c)’s relaxed
residency requirements for citizen mothers. See id., at 17–
19, 42–43, 44, n. 23. But petitioners do not challenge here
the distinction between § 1401(g), which requires that citizen
fathers have previously resided in the United States for five
years, including at least two years after the age of 14, and
§ 1409(c), which provides that a citizen mother need only
have resided in the United States for one year. The INS’
proffered justification of statelessness thus does nothing to
buttress the case for § 1409(a)(4).
The Court also makes a number of observations that tend,
on the whole, to detract and distract from the relevant equal
protection inquiry. For example, presumably referring to
§ 1409 in general, the majority suggests that “the statute
simply ensures equivalence between two expectant mothers
who are citizens abroad if one chooses to reenter for the
child’s birth and the other chooses not to return, or does not
have the means to do so.” Ante, at 61. But even apart
from the question whether this was one of Congress’ actual
purposes (and the majority does not affirmatively claim that
it was), this equivalence is quite beside the point of petition-
ers’ constitutional challenge, which is directed at the dissimi-
lar treatment accorded to fathers and mothers.
The Court also states that the obligation imposed by
§ 1409(a)(4) is “minimal” and does not present “inordinate
and unnecessary hurdles” to the acquisition of citizenship
by the nonmarital child of a citizen father. Ante, at 70.
Even assuming that the burden is minimal (and the question
whether the hurdle is “unnecessary” is quite different in kind
from the question whether it is burdensome), it is well set-
tled that “the ‘absence of an insurmountable barrier’ will not

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redeem an otherwise unconstitutionally discriminatory law.”
Kirchberg, 450 U. S., at 461 (quoting Trimble v. Gordon, 430
U. S. 762, 774 (1977)).
Finally, while the recitation of statistics concerning mili-
tary personnel and overseas travel, ante, at 65–66, highlights
the opportunities for United States citizens to interact with
citizens of foreign countries, it bears little on the question
whether § 1409(a)(4)’s discriminatory means are a permissi-
ble governmental response to those circumstances. Indeed,
the majority’s discussion may itself simply reflect the stereo-
type of male irresponsibility that is no more a basis for the
validity of the classification than are stereotypes about the
“traditional” behavior patterns of women.
It is, of course, true that the failure to recognize rele-
vant differences is out of line with the command of equal
protection. See ante, at 73. But so too do we undermine
the promise of equal protection when we try to make our
differences carry weight they simply cannot bear. This
promise informs the proper application of heightened scru-
tiny to sex-based classifications and demands our scrupulous
adherence to that test.
III
The Court identifies two “additional obstacles” that peti-
tioners would face even were the Court to accept the con-
clusion that the statute fails heightened scrutiny. Ante, at
71. The first question concerns “ ‘potential problems with
fashioning a remedy.’ ” Ante, at 72 (quoting Miller, 523
U. S., at 451 (O’Connor, J., concurring in judgment) (citing
id., at 452–459 (Scalia, J., concurring in judgment))). The
second question concerns “the implications of statements in
our earlier cases regarding the wide deference afforded to
Congress in the exercise of its immigration and naturaliza-
tion power.” Ante, at 72–73. I believe that petitioners are
able to surmount both of these hurdles.
As to the matter of remedy, severance of § 1409(a)(4) would
have been appropriate had petitioners prevailed. Several

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95 Cite as: 533 U. S. 53 (2001)
O’Connor, J., dissenting
factors support this conclusion. The Immigration and Na-
tionality Act (INA) contains a general severability clause,
which provides: “If any particular provision of this Act,
or the application thereof to any person or circumstance,
is held invalid, the remainder of the Act and the application
of such provision to other persons or circumstances shall not
be affected thereby.” § 406, 66 Stat. 281; see note following
8 U. S. C. § 1101, p. 38, “Separability.” We have concluded
that this severability clause “is unambiguous and gives rise
to a presumption that Congress did not intend the validity
of the [INA] as a whole, or any part of the [INA], to depend
upon whether” any one provision was unconstitutional.
INS v. Chadha, 462 U. S. 919, 932 (1983).
Title 8 U. S. C. § 1421(d), which states that “[a] person may
only be naturalized as a citizen of the United States in the
manner and under the conditions prescribed in this sub-
chapter and not otherwise,” has no effect on the operation
of the INA’s general severability clause in this case. Section
1421(d) governs only naturalization, which the statute de-
fines as “the conferring of nationality of a state upon a per-
son after birth,” § 1101(a)(23), whereas §§ 1401(g) and 1409
deal with the transmission of citizenship at birth, see § 1401
(“The following shall be nationals and citizens of the United
States at birth . . .”). Further, unlike the INA’s general
severability clause, § 1421(d) does not specifically address
the scenario where a particular provision is held invalid.
Indeed, the INS does not even rely on § 1421(d) in its brief.
Nor does our decision in INS v. Pangilinan, 486 U. S. 875
(1988), preclude severance here. In Pangilinan, this Court
held that courts lack equitable authority to order the natu-
ralization of persons who did not satisfy the statutory re-
quirements for naturalization. Id., at 883–885. Petitioners
in the instant case, however, seek the exercise of no such
equitable power. Petitioners instead seek severance of the
offending provisions so that the statute, free of its con-
stitutional defect, can operate to determine whether citizen-

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96 TUAN ANH NGUYEN v. INS
O’Connor, J., dissenting
ship was transmitted at birth. Cf. Miller, supra, at 488–489
(Breyer, J., dissenting).
In addition to the severance clause, this Court has often
concluded that, in the absence of legislative direction not
to sever the infirm provision, “extension, rather than nul-
lification,” of a benefit is more faithful to the legislative de-
sign. Califano v. Westcott, 443 U. S. 76, 89–90 (1979); see
also Weinberger v. Wiesenfeld, 420 U. S. 636 (1975); Fron-
tiero, 411 U. S., at 691, n. 25. The choice of extension over
nullification also would have the virtue of avoiding injury to
parties who are not represented in the instant litigation.
And Congress, of course, remains free to redesign the stat-
ute in a manner that comports with the Constitution.
As to the question of deference, the pivotal case is Fiallo
v. Bell, 430 U. S. 787 (1977). Fiallo, however, is readily
distinguished. Fiallo involved constitutional challenges to
various statutory distinctions, including a classification
based on the sex of a United States citizen or lawful per-
manent resident, that determined the availability of a special
immigration preference to certain aliens by virtue of their
relationship with the citizen or lawful permanent resident.
Id., at 788–792; see also Miller, supra, at 429 (opinion of
Stevens, J.). The Court, emphasizing “the limited scope
of judicial inquiry into immigration legislation,” 430 U. S.,
at 792, rejected the constitutional challenges. The Court
noted its repeated prior emphasis that “ ‘over no conceiv-
able subject is the legislative power of Congress more com-
plete than it is over’ the admission of aliens.” Ibid. (quot-
ing Oceanic Steam Nav. Co. v. Stranahan, 214 U. S. 320,
339 (1909)).
The instant case is not about the admission of aliens but
instead concerns the logically prior question whether an in-
dividual is a citizen in the first place. A predicate for ap-
plication of the deference commanded by Fiallo is that the
individuals concerned be aliens. But whether that predicate
obtains is the very matter at issue in this case. Cf. Miller,

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O’Connor, J., dissenting
523 U. S., at 433, n. 10 (opinion of Stevens, J.) (“[T]he Gov-
ernment now argues . . . that an alien outside the territory
of the United States has no substantive rights cognizable
under the Fifth Amendment. Even if that is so, the ques-
tion to be decided is whether petitioner is such an alien
or whether, as [petitioner] claims, [petitioner] is a citizen.
Thus, we must address the merits to determine whether
the predicate for this argument is accurate” (internal quota-
tion marks and citation omitted)). Because §§ 1401 and 1409
govern the conferral of citizenship at birth, and not the ad-
mission of aliens, the ordinary standards of equal protection
review apply. See id., at 480–481 (Breyer, J., dissenting).
* * *
No one should mistake the majority’s analysis for a careful
application of this Court’s equal protection jurisprudence
concerning sex-based classifications. Today’s decision in-
stead represents a deviation from a line of cases in which we
have vigilantly applied heightened scrutiny to such classifi-
cations to determine whether a constitutional violation has
occurred. I trust that the depth and vitality of these prece-
dents will ensure that today’s error remains an aberration.
I respectfully dissent.