(a) The following persons may adopt: (1) a husband and wife together;
(2) an unmarried adult;
(3) the unmarried father or mother of the person to be adopted;
(4) a married person without the other spouse joining as a petitioner, if the person to be adopted is not the other spouse, and if (A) the other spouse is a parent of the person to be adopted and consents to the adoption;
(B) the petitioner and the other spouse are legally separated;
(C) the person to be adopted is an adult and the other spouse consents to the adoption; or
(D) the failure of the other spouse to join in the petition or to agree to the adoption is excused by the court by reason of prolonged unexplained absence, unavailability, incapacity, or circumstances constituting an unreasonable withholding of consent.
(b) Nothing in this section affects legitimation under AS 25.20.050.