Aversion to inbred men isn't just a sensible cultural tradition. It might be biologically hard-wired into women who are literally able to sniff out the scent of incest.

In a study published today in Current Biology, researchers from the

University of Liverpool bred two groups of male mice to be identical in every way but one: the diversity of their so-called major urinary proteins.

Lacking Google stalking and the advice of embittered friends, female mice rely on urinary proteins for information about potential mates. In the wild, mice born to genetically unrelated parents have more varied proteins than the offspring of related parents – and in the Liverpool lab, female mice consistently picked males with the most complex urinary bouquet.

Do human women have the same ability? Scientists don't know

\– but it's certainly plausible. Olfactory cues are among the tricks we instinctively use to detect unsuitable mates. (That said, some animals prefer inbreeding – and in certain circumstances,

"kissing cousins" might have an advantage.)

A non-scientific aside: a lot of jokes came to mind for this post and are entirely unfit to print. That's probably for the better. But it's a shame this study didn't come out five years ago – it would have made a great plot device for an episode Friends or Seinfeld.

The Direct Assessment of Genetic Heterozygosity through Scent in the Mouse [Current Biology]

Image: Francisco Goya's "The Family of Charles IV." Credit to WiSci colleague Alexis Madrigal for suggesting royalty to illustratively convey inbreeding – and nothing says inbreeding like Goya's depictions of Spanish (ig)nobility.*

See Also:

WiSci 2.0: Brandon Keim's Twitter and Del.icio.us feeds; Wired Science on Facebook.