D.C. Code § 16-302: Persons who may adopt.

Any person may petition the court for a decree of adoption. A petition may not be considered by the court unless petitioner’s spouse, if the petitioner has one, joins in the petition, except if either spouse is a natural parent of the prospective adoptee, the natural parent need not join in the petition with the adopting parent, but need only give consent to the adoption. If the marital status of the petitioner changes after the time of filing the petition and before the time the decree of adoption is final, the petition must be amended accordingly.