Okla. Stat. tit. 10, § 10-7507-1.1: Adult adoptions

An adult person may be adopted by any other adult person, with the

consent of the person to be adopted or his guardian, if the court

shall approve, and with the consent of the spouse, if any, of an

adoptive parent, filed in writing with the court. The provisions of

Sections 9 through 36 of this act shall not apply to the adoption of

a competent adult person. A petition therefor shall be filed with

the district court in the county where the adoptive parents reside.

After a hearing on the petition and after such investigation as the

court deems advisable, if the court finds that it is to the best

interests of the people involved, a decree of adoption may be

entered which shall have the legal consequences stated in Section 37

of this act.