♦ AM's wife walked out on him without telling him he was about to become a father. A chance meeting with his wife, who had since remarried, brought him face-to-face with his teenage son, who was his spitting image. AM remains a single father bereft of any contact with his son.

♦ For Dharmendra Kumar, marriage was never the driving concern; fatherhood was. As a single man his only option was to adopt, and only boys by law. Five years ago, he adopted a son. He has now applied for a second adoption.

A recent Supreme Court judgment in a case maintaining a single unwed mother's right to keep private her child's paternity from an uninvolved father has been welcomed as a progressive verdict for single women.

But single men have welcomed the verdict, too. The court referred to the legal definition of a parent in gender-free terms under certain sections of the law, stoking the debate on the rights of single fathers.

The single father species in India is not as narrow a group as one may think. But the definition is no longer restricted to men who bring up their children single-handedly - they also apply to fathers who are single. Some take care of their offspring after being divorced or widowed, some adopt - and some, like AM, just yearn for them.

Arvind Nanda adopted his first son in 1997. The law had then just changed to allow single males to adopt. Now 60, Nanda, the CEO of manufacturing company Interarch, has two adopted sons, aged 19 and 12 who think their "Dad is cool".

At the other end of the spectrum are single fathers who are so by circumstances, which can often be contentious such as divorce or separation.

Take the case of Rajesh Rao. Three years after their love marriage, his wife became pregnant and went to her parents' home. She never returned. Rao was at the hospital for the birth of their son and spent five days with him. The sixth day, his wife told him flatly that she was not coming back and would never give him the baby. A few months later he was given an ultimatum: either grant her a divorce with a promise not to see the child or face a dowry harassment charge that carried instant jail time.

Rao gave up all his legal rights but pleaded to be allowed to see his son periodically. "The mother has every right to the baby so it is unethical for me to snatch away the baby. But at least once a day or even once a week, I should have been allowed to see him," Rao says wretchedly. His biggest dilemma was that his former wife stayed in the same neighbourhood but as a single dad he couldn't go over to see his son.

Rao's parents saw him slip into depression and arranged a couple of years later for him to remarry. He and his wife have a daughter. "Whatever I missed out on doing with my son I get to do with my daughter, be it holding her in my arms, feeding her or seeing her baby steps. But I never say I have two children, which will only invite questions."

The Supreme Court verdict has sparked hope in single dads who are not allowed visitation rights. Rao's biggest regret is that despite the divorce with mutual agreement, at the hearing the judge did not once mention the father's right to the child.

"I had hoped he would. He only asked me how much do you earn? His second question to my wife was how much do you want from him. She did not want money, just the child," he says.

Single men wanting to be biological parents - through surrogacy - are unhappy, too. The surrogacy route no longer exists for them. It is an option now available only to "married infertile couples who have been married for at least two years".

Dipankar Sen (name changed) was lucky. Ten years ago, before the surrogacy laws were tightened, the Calcutta-based chartered accountant was able to fulfil his wish to have a baby via surrogacy despite being single.

Dr Sudardshan Ghosh Dastidar, at whose fertility clinic Sen became a proud father, says that requests from single men to have children via surrogacy are not common. "Our ethical committee interviewed him (Sen) extensively. We felt he was a good candidate," Dr Ghosh Dastidar says.

Voices are now being heard about allowing single parenting via surrogacy. "It is the right of individuals to lead their lives the way they want. And if single men want to be fathers, they should have the option," says Dr Rajesh Vaidya, obstetrician and infertility specialist, who runs a fertility clinic in Mumbai.

On the sidelines of the debate, another question is being raised: should single men also be allowed to adopt girls? Dharmendra Kumar wanted to do so, but the law didn't let him. "It may be questionable but this is done to reduce chances of sexual abuse or trafficking," says Darshana Mitra, advocate, Alternative Law Forum.

Nanda contends that with official adoption rates being stunted ("1,400 a year") and illegal adoptions on the rise, it is the orphaned child who misses out, thanks to an imperfect system and rules. "I still seethe when I remember the judge asking me, are you adopting for commercial use?"

Alongside, concern is being voiced over men who miss out on fatherhood because the law tilts towards mothers in custodial cases. "The traditional family structure is codified in law. The father is seen as the natural guardian and the mother as natural custodian," Mitra explains. "The guardian administers property and all decisions with respect to the child. Thus, the insistence for the father's signature for a school certificate. Young children, at least till the age of five, are in the natural custody of the mother."

In custody battle issues, therefore, Mitra says, the mother usually get custody unless she is shown to be singularly unfit which the father then has to prove, but the mother does not have to prove the father is unfit. When it comes to visitation rights, if the mother wants to deny the father, she must prove he is unfit.

But for single dads removed from their children, there may be some hope. In 2013, the Karnataka High Court ordered that the estranged parents of an 11-year-old boy would alternately keep him for six months. The custody battle began when the child was one. At the time of the verdict, the divorce was still pending in family court.