Hindu Adoptions and Maintenance Act, 1956
10. Persons who may be adopted
No person shall be capable of being taken in adoption unless the following conditions are fulfilled, namely,-
(i) he or she is Hindu;
(ii) he or she has not already been adopted;
(iii) he or she has not been married, unless there is a custom or usage applicable to the parties which permits persons who are married being taken in adoption;
(iv) he or she has not completed the age of fifteen years, unless there is a custom or usage applicable to the parties which permits persons who have completed the age of fifteen years being taken in adoption.