We are used to the sad stories of children who have never known their fathers, and of those whose fathers become estranged through divorce; but there are a growing number of children who risk losing the only father they have ever known because he discovers he is not their father after all.

The New York Times Magazine ran a long article recently on the issue of men taking DNA tests to establish paternity status when they are in dispute with their wife, or when they have been named as the father of a child under welfare rules. Their aim is to avoid paying child support.

The biggest issue here -- especially when it involves the break-up of a family after a number of years -- is the devastating effect on a child of what can amount to losing a father twice over. In one instance, a divorced man walked out of his putative daughter’s life when she was 11 and refused all contact with her. Now 20, she says:

“It kind of wrecked my self-esteem,” she says. “Even now, I worry about being a burden on people. I don’t want to be in the way. I don’t want to be anybody’s problem. It’s made me apprehensive about getting attached to people, because one day they’re there and the next day maybe they won’t be. You can’t help but be careful.”

Ruth Padawer, an adjunct professor at Columbia University’s Graduate School of Journalism, discusses the case of Mike L, which went to an appellate court in Pennsylvania where it was knocked back. This man’s suspicions were first aroused when his daughter, L, was nearly three and confirmed two years later when the couple and the little girl all had a DNA test. The couple separated immediately, but Mike, to avert the risk of losing access to the child, signed a form saying he was the natural father and began paying child support.

Then it got more complicated. Mike married again. Then his first wife told him she was marrying X, the child’s biological father. Mike became bitter about paying child support to the advantage of X and, urged on by his new wife, went to court to get rid of his financial obligations. At that point he told his nine-year-old de facto daughter the situation, reassuring her he would fight to retain custody rights. He lost his case for maintenance relief, but the judge was sympathetic.

State statutes and case law vary widely, but most judges conclude that these men must continue to raise their children — or at least pay support — no matter what their DNA says.

“The laws should discourage adults from treating children they have parented as expendable when their adult relationships fall apart,” Florida’s top court held in a 2007 paternity decision, quoting a law professor. “It is the adults who can and should absorb the pain of betrayal rather than inflict additional betrayal on the involved children.”

“The scientific advance that was supposed to offer clarity instead reveals just how murky society’s notions of fatherhood actually are,” Padawer comments.

Various solutions are proposed. Some judges are urging a law change or court ruling to grant them the discretion to consider DNA as one of many factors, along with the history of the relationship and the child’s age, in determining who should raise a child and who should pay for his or her upkeep. In other words, maybe a nonbiological father could be granted custody rights even if the biological father is charged with paying support.

Another proposal would allow the presumed father, the biological father or the mother to challenge the paternity until a child turns two.

Yet another suggestion is that DNA paternity tests should be routine at birth, or at least before every paternity acknowledgment is signed and every default order entered. Some advocates propose a somewhat more practical solution: that men who waive the DNA test at a child’s birth should be informed quite clearly that refusing the test will prohibit them from challenging paternity later.

Padawer’s take on the whole issue is that too much importance is being attached to genetic relationships, as though DNA had an almost magical power to bond people. She notes:

Child-welfare advocates say that making biology the sole determinant of paternity in cases like Smith’s puts the nonbiological father’s interest above the child’s. Besides, society has increasingly recognized that parenthood is not necessarily bound to genetics. Reproductive technology has made it possible for one person to supply an egg, another to fertilize it, a third to gestate it and a fourth and fifth to be deemed the parents. Stepparents, grandparents and same-sex co-parents are increasingly winning legally protected access to children whom they helped raise, even when no direct genetic link exists.

One can agree with Padawer up to a point: it’s not just DNA that makes a parent -- as we see from the countless successful adoptions on the one hand, and, on the other, the countless male begetters who disappear from the scene. But it is too convenient to downplay the biological factor for the sake of justifying the various ways in which parenthood is engineered today -- donor gametes in IVF, same-sex parenting and so on. This is what I sense Padawer is doing.

Moreover, the social pathology underlying the trend she describes is what we should really be tackling: the sexual promiscuity that can lead to real doubts about paternity and anyway makes marriage more difficult to achieve and sustain; the increasing number of non-marital births (40 per cent of all births in the US); and the high rates of marital breakdown, which becomes the occasion for disputes about everything -- including paternity.

And all to the great distress and disadvantage of children.