Similar question was asked by one Dr. Raghu and I replied to him. This may be useful to you:
Dr. Raghu, the issue which you raised has been tormenting a lot of stepfathers and stepmothers who wish to be the natural parent of the stepchild. There are two schools of thought about this issue. One says that a stepfather can never be adoptive father due to the language used in HAMA (Hindu Adoption and Maintenance Act), which prohibits natural mother to become adoptive mother. The second school of thought is that stepfather gets a court order as a guardian with the help of natural mother and on the basis of that order, gets adoptive father order under HAMA Act. As it baffles you, I tell you easy process:1. Youmust be a Hindu and that girlchild also must be Hindu. 2. There must be age difference of atleast 21 years between the child and you. If you meet these requirements, then try to get the consent of biological father in writing on the adoption deed. (Adoption deed has to be prepared by competent advocate). It bears the signature of biological father, mother giving in adoption to you and your signature in the presence of two competent witnesses. Get this adoption deed registered before the Registrar of the District. Then after registration, issue newspaper publication and also gazette publication changing the surname of the child to your surname, only if she is carrying the surname of the biologial father. If you have any difficulty to get the signature of the biological father on adoption deed, then on the strength of the court order giving the biological mother the full rights as guardian can be used to get the adoption deed valid in the eyes of law. A lot of bureaucratic innvolvement is required, as you know, there will be hurdles and they can be overcome by entertaining them with good humour. Wish you best of luck.
Prabhakar Advocate (M)9958670740
Legal Aid panelist - family law - Central Delhi (Tis Hazari)