Daddy Discrepancy

When it comes to establishing paternity, the widely used (but unsubstantiated) figure of 10% paternal discrepancy may be an overestimate for most populations:

New British research is rattling the roots of the family tree, citing paternity "discrepancy" in perhaps 4% of fathers studied.

"Paternal discrepancy" is a delicate term for a loaded subject. It refers to a man who wrongly thinks he's a child's biological father.

Paternal discrepancy was studied by researchers including Professor Mark Bellis, director of the Centre for Public Health at Liverpool John Moores University in England.

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Bellis and colleagues checked studies from the 1950s through 2002 that mentioned paternal discrepancy. The studies came from the U.K., U.S., Europe, Russia, Canada, South Africa, South America, New Zealand, and Mexico.

Over the years, few studies directly tackled the topic. For instance, some researchers set out to screen for multiple sclerosis or cystic fibrosis, noting paternal discrepancies along the way.

Some studies were large; others included a handful of people. Paternal-discrepancy estimates varied wildly, from less than 1% to more than 30%.

But those numbers don't tell the whole story.

Some research centered on paternity disputes. Daddy discrepancies were probably overrepresented in those studies, writes Bellis.

Setting those studies aside, the remaining research showed an average paternal discrepancy of 3.7%, or a little less than one in 25 dads, write the researchers.

Don't Jump to Conclusions

That number doesn't necessarily mean that out of 25 dads at the ballpark, one isn't really his child's biological father.

Because the researchers extrapolated some information from studies involving topics other than paternity, they say that the percentage is not a true indication of paternal discrepancies in the general population. However, "it does suggest the widely used (but unsubstantiated) figure of 10% paternal discrepancy may be an overestimate for most populations," write the researchers.

In other words, paternal discrepancy might be rarer than commonly thought.