No person shall be capable of being taken in adoption unless the following conditions are fulfilled, namely:―
(i)he or she is a 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.