“Are you my daddy?”

In Porgy and Bess, caddish Sportin’ Life lures Bess from virtuous Porgy by crooning “the things that you’re liable to read in the Bible, well, it ain’t necessarily so.” Sportin’ Life could just as easily have been talking about the assumption that most men make—that their children are really their children. Many times, well, it just ain’t necessarily so.

According to the American Association of Blood Banks, 30 percent of men taking paternity tests in 2000 were not the biological fathers of their children. And we are not just talking about Joe Six-pack single men, either. Minneapolis family attorney Nancy Berg reports that she has married clients from Edina who get the rude surprise of a tomcat from the cheating side of town. Berg says, “Married men can and do find themselves paying for kids that are not their biological offspring.”

Consider the story of Texas engineer Morgan Wise. His wife Wanda gave birth to four children during the marriage, one of which had cystic fibrosis. After the divorce, Wise took a blood test to find out which cystic fibrosis gene he carried and, to his surprise, found that he did not carry the gene at all. Since both parents must be carriers for a child to inherit the gene, Wise could not possibly be the father of that child. Later tests confirmed that only one of Wanda’s four children were his. (The Texas courts not only rejected his request to reduce his child support payments; Wise was later forbidden to have contact with any of the children because he violated a court order by telling them the truth about their parentage.)

Patrick McCarthy, a New Jersey man who discovered after his divorce that his 14-year-old daughter was fathered by another man, founded New Jersey Citizens Against Paternity Fraud. His organization convinced New Jersey Assemblyman Neil Cohen to sponsor legislation allowing men to use DNA tests to disprove paternity and end financial support.

In both cases, where was the biological father? Laughing all the way to the bank. Not surprisingly, many women’s groups and child advocates are fighting the New Jersey effort every step of the way. A National Center for Youth Law staff lawyer in Oakland, California says, “Families are much more than biology.”

Until now, Minnesota judges believed that the “child’s best interests” trumped biology nearly every time. St. Paul’s Lionel Suggs and lawyer John Westrick, however, recently convinced the Minnesota Court of Appeals that it ain’t necessarily so. Suggs’ girlfriend had duped him into believing that he had fathered her child. After the child was born, Suggs’ found out through a DNA test that, as Michael Jackson sang in “Billie Jean,” that the kid was not his son. Ramsey County judge Joanne Smith said the “best interests of the child” required keeping Suggs on the child support hook. The appellate court begged to differ, making it clear that biology, not the child’s best interest, would be (in the words of Suggs’ attorney) the “trump card.” At least as far as that goes, for Lionel Suggs.

According to family law guru Berg, Turner v. Suggs has taken a “man’s issue” and used it to unleash a Pandora’s box of clashing policy issues. “Ever since Genesis, men have wondered, Is the kid really mine? And ever since Genesis, all women have secretly hoped and prayed that the baby looks at least a little like the father because they know how men think. Families that would have rolled along reasonably happy and content are being torn up by information that, in an earlier time, would not have seen the light of day.”

Does that mean that biological fathers should evade child support just because another man is available? Berg is torn. “I do not think we should start down a road that could compromise family relationships from the very beginning.”

Why not make paternity testing a routine part of the birthing process, just like we routinely test for sickle cell and myriad other things? For most couples, there will not be any surprises. And for those who find out that it ain’t necessarily so, why not get that information out in the open and make sure the real papa helps to pay the bills?