Who's the daddy? Paternity mixed up in cities, study finds

Illegitimacy more likely over past 500 years among urban poor, say geneticists

The Romans had a phrase that summed it up nicely: mater semper certa est, pater semper incertus est. The mother is always certain, the father is always uncertain.

Now, researchers have found that some people have more reason to doubt their fathers than others, or at least have had over the past half millennium.