MONDAY, April 17, 2006 (HealthDay News) -- Ninety-eight percent of men raising children they believe to be their biological offspring are right to think so, according to the largest review of paternity and genetic test data ever conducted.
Even men who actively seek out paternity tests because they doubt their paternity turn out to be wrong most of the time, the study found.
"Only about 30 percent of those men aren't the father," said researcher Kermyt Anderson, an assistant professor in the department of anthropology at the University of Oklahoma.
He said the findings should help squelch the long-standing myth, promulgated over the last few decades, that more than 10 percent of all fathers are unknowingly raising children who are not biologically their own.
Combing through data from 67 different studies, Anderson found the number "to be closer to just 2 percent of men. Very few of them are being deceived."
The findings appear in the upcoming June issue of Current Anthropology.
Anderson said improvements in genetic testing coupled with rising divorce rates have made paternity screening a "growing industry," with the dramatic results of these tests read live daily on The Jerry Springer Show and other "shock-talk" programming.
And for reasons linked to the potential for child-support claims, "some U.S. states have also been very big in recent years on trying to get men named on birth certificates as biological father," Anderson said. "Especially in the case of unmarried parents, but even among married parents, legal fatherhood is being established early on."
But the vast majority of dads wondering "Who's your daddy?" can rest easy, he said. "There's not much basis for the figure of 10 percent or even 10 to 20 percent non-paternity that's been kicked around," Anderson said.
For the study, the Oklahoma researcher pored over dozens of studies from countries around the globe. Some of them looked at paternity-test results from men taking gene tests for reasons unrelated to their status as fathers (i.e., they did not doubt their paternity as they underwent testing). Others data came from commercial paternity-test clinics, where most clients did have reservations about their status as a biological parent.
However, the new study found unsuspected non-paternity to be a relatively rare phenomenon, with rates more or less similar among the United States, Canada and Europe. Among men who felt confident they were the biological father of their child, the highest rate of actual non-paternity was found in men from Mexico -- just over 8 percent.
Men who discover they are not the biological father of a child or expected child often react negatively, Anderson said.
"First of all, if there's a pregnancy involved, that pregnancy is more likely to be aborted," he said. "And they were also more likely to divorce or separate from the women. Men spend less time with kids after divorce, of course, but even controlling for that, they spend less time with kids after divorce if they think they are not their own kids."
An earlier study, released last August, found that more and more men are finding out they are not the father of their child via results from routine medical tests. These gene-based tests are often conducted for a variety of medical reasons unrelated to paternity, such as disease-screening or organ transplant.
"At the moment, people are often receiving the results of [this] paternity testing through e-mail and post," lead researcher Mark Bellis, a professor of public health at Liverpool John Moores University in England, told HealthDay.
But Anderson stressed that biology isn't everything, especially if a man has already developed a strong bond with the children under his care.
"Much of this is about broad statistics," he said. "Biological dads can be very neglectful, too, and stepdads can be very caring."
For more on paternity testing, visit the American Pregnancy Association.