Questione giuridica chiave
Whether the agreement between the mother and stepfather could be treated as a child-support contract under Arts. 287 and 288 CC and affect the father's maintenance duty.
Decisione estratta
No. Only the legal parents and the child can be parties to a child-support contract; agreements with third persons are merely contractual and cannot alter the child's statutory claim.
Motivazione estratta
The support duty is family-law based and tied to the parent-child relationship. Because the stepfather was not a legal parent, the 'support guarantee' had only obligational effect and could not amend the prior court settlement or be approved as a child-support agreement.