An adult may be adopted with consent.Most Relevant New York Statutes:
Domestic Relations, Article 7, Title 1
§ 111 111. Whose consent required.
1.(a) Of the adoptive child, if over fourteen years of age
4. Where the adoptive child is over the age of eighteen years the consents specified in paragraphs (b), (c) and (d) of subdivision one ofthis section shall not be required, and the judge or surrogate in his discretion may direct that the consent specified in paragraph (f) of subdivision one of this section shall not be required if in his opinion the best interests of the adoptive child will be promoted by the adoption and such consent cannot for any reason be obtained.