As with most things which the goddess of natural selection cannot explain, this one'll be dumped off on the goddess of sexual selection. One could always google, but I'm confident enough in my evolutionology to speak first & google later.

It'll be claimed either men long ago preferred women without facial hair, or that women long ago preferred men with facial hair. The sexual selection goddess is overloaded trying to explain humans, for in some cases it's the males doing the selecting, but most of the time it's the females. In order to obtain consistent results, it'd have to be one or the other (and even then it doesn't really work if you think more than one or two thoughts about it). Darwin always preferred to claim women did all the selecting, and even females among the animals.

Don't expect a satisfactory answer. Do expect a weak chuckle. Really, why would females of a species which was previously indifferent all of a sudden take to having strong, particular preferences? And if they did, what good would it do them? Their competition, the "old fashioned" females would be quite happy about this idea, one expects.

Dark Matter + Dark Energy = Dark Truth

"We find that such evidence demonstrates that the ID argument is dependent upon setting a scientifically unreasonable burden of proof for the theory of evolution." - Judge Jones Kitzmiller case
http://www.talkreason.org/articles/Falsify.cfm

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