Answered: All Your Nagging Questions About Testicle Location

By Andrew Moseman | November 20, 2009 3:45 pm

sperm220As 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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Image: iStockphoto

  • Brian Too

    Really? They are “terribly exposed?” If they must be outside the body, where pray tell is a better protected location? On the elbow? How about on top of the head? Chest area? How about back of the wrist? Shin?

    Seems to me between the legs is better than just about all the alternatives. You’ve got a leg on either side and a pelvis directly above. That’s decent protection.

  • Mari-O

    Apparently, the testes are well-protected enough by a combination of (i) location and (ii) the instinct that all males have to shield the genitals with the hands in case of proximate danger. Otherwise, humans would have either evolved sperm that could survive inside an internal pouch, or perhaps developed a cartilaginous scrotal sheath. Were that not enough we might even be looking at a pelvic exoskeleton protecting the nether regions.

    It’s a funny idea but I don’t think low-hanging fruit ever attracted a woman. If anything, the penis itself might theoretically serve the peacocking function. But I somehow doubt females are as hardwired on a primordial level to respond to discrete body parts as men.


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