New York

Can a known donor renounce his legal obligations as a parent?

New York has no sperm donor legislation.  Therefore, donors to unmarried persons, regardless of whether a clinic was involved in the insemination process or not, could potentially be determined to be legal fathers (although going through a clinic may affect parentage rights in another state if they move, and certainly clarifies intent better).

What if a known donor attempts to enforce his parental rights when the original intent was to be a sperm donor only?

Courts in NY state have allowed a known donor to pursue legal parental rights, despite an oral agreement between the parties to the contrary.

Does the state allow for second-parent adoption (i.e., for same-sex couples)?

Yes.  As NY permits same-sex marriage, a second-parent adoption is only required when the intended parents are unmarried.

Does the state allow for multiple-parent families (when the child has more than two adults in a parenting role)?

Unknown; this issue has not yet been addressed.

Does the state recognize “de-facto” or “psychological” parentage (of an “acting” parent without a biological connection)?

Yes.