Evolutionary links between monogamy and fatherhood are more complicated than we thought

Compared with our closest relatives, the common chimpanzee and the bonobo, humans are pretty good at focusing exclusively on one mate at a time.

Just how exclusively, however, is the subject of endless tabloid gossip, culture-war sabre-rattling, and scientific debate. The answer seemed to be that most people are exclusive most of the time, but new evidence has thrown the question wide open again.