Why are testicles kept in a vulnerable dangling sac? It’s not why you think.
Some of you may be thinking that there is a simple answer: temperature. This arrangement evolved to keep them cool. I thought so, too, and assumed that a quick glimpse at the
scientific literature would reveal the biological reasons and I’d move on. But what I found was that the small band of scientists who have dedicated their professional time to
pondering the scrotum’s existence are starkly divided over this so-called cooling hypothesis.