As you've probably heard, a man's testicles hang down because sperm are hyper-sensitive to temperature and need to be a little cooler than the inside of the body. But isn't there more to it than that? Oh, definitely yes, says research psychologist Jesse Bering, writing for Scientific American. Bering goes on at great length in his analysis of testicular location. Sure, he argues, the temperature part makes sense. But why would natural selection, which so rewards passing on your genes, put a man's means of passing on those genes in such a terribly exposed place on his body? Bering's lengthy account of gonad geography, and the studies trying to explain it, includes some real gems:
One of the more fanciful accounts--and one ultimately discarded by the authors--is that scrotal testicles evolved in the same spirit as peacock feathers. That is to say, given the enormous disadvantage of having your entire genetic potential contained in a thin satchel of unprotected, delicate flesh and swinging several millimeters away from the rest of your body, perhaps scrotal testicles evolved as a sort of ornamental display communicating the genetic quality of the male.
Oh, and this, on how a man's cremasteric muscle works to keep his sperm at an optimal temperature by contracting and drawing the testicles up on a cold day and relaxing when it's hot:
[That's] why it’s generally inadvisable for men to wear tight-fitting jeans or especially snug “tighty whities”--under these restrictive conditions the testicles are shoved up against the body and artificially warmed so that the cremasteric muscle cannot do its job properly. Another reason not to wear these things is that it’s no longer 1988.
In all seriousness, there's nothing Discoblog values more than analysis of the silly... other than over-analysis of the silly. If you haven't had your fill of scrotal hypotheses, check out the rest of Bering's post
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