What percentage of babies are estimated to come from extra-pair copulations?

• A. 1%
• B. 3-4%
• C. 5-6%
• D. 8-9%

Answer: (B)

Understanding how often extra-pair copulations result in a baby hinges on distinguishing social paternity from biological paternity. When scientists use genetic testing to determine the actual father, they consistently find that a small but real portion of children are not fathered by the mother's social partner. In humans, the typical non-paternity rate shown by DNA studies is around three to four percent, which is why this range best matches the evidence. Rates can vary by population and method, but the low single-digit range is the common center of the data. Smaller rates, like one percent, are at the low end of observed variation, while higher rates such as five to six percent or eight to nine percent are less aligned with the broad body of genetic-paternity research outside specific contexts.