In Cosmopolitan there is a regular section ““Understanding His Baffling Behavior” purporting to “explain” to the magazine’s predominantly female audience why men behave as they do.
Recently they asked, Why do men sit with their legs splayed? Their answer,
Women are taught to keep their legs together as a way of not inviting sex,” says Helen Fisher, PhD, author of The First Sex: The Natural Talents of Women and How They Are Changing the World (Ballantine, 2000). “In contrast, a man is saying, ‘Come and get it.’
No, no, and no. As one male blogger stressed, “It is a comfort factor.” Sitting with legs together squishes your balls between your thighs — certainly not comfortable, any man can tell you. The blogger is right, but missed the bigger picture: there is more to it than comfort. As a matter of fact, it is all about maintaining the testes at the right temperature.
Did no one ask, during sex education class in school, the obvious question of why men have balls hanging outside their bodies? What do balls — the testes — do? Why is the male anatomy the way it is?
The testes are not inside with the rest of the body’s organs for a well-known reason: sperm reproduction needs to occur at a temperature about 2 degrees cooler than basal body temperature. The wrong temperature leads to increased DNA replication errors, and it leads to sperm with poor motility or even semen with mostly “dead” or damaged sperm.
So men, like the males of many mammals, have ballocks or ball-sacks which suspend the testes outside the body so they can be maintained at the right temperature. It is a flexible solution. The cremasteric muscle can contract to draw the balls up into the crotch to be warmed by contact with the rest of the body, or relax to suspend the testes in mid-air to be cooled by air convection (this is known as the cremasteric reflex). If necessary the male can also open or close his legs to change testes temperature by increasing or decreasing contact with his warmer body.
Civilization complicates the natural cooling of the testes by imposing pants and underpants on men. These add unwelcome warmth to the testicles, both due to the normal warming effect of clothing and due to pressing the balls tight against the crotch. This defeats nature’s purposes, reducing sperm count and motility, increasing DNA copying errors, and consequently leads to more birth defects and increased infertility. Healthy spermatogenesis is thus one of the most important benefits of male nudity.
Still, even in societies petrified by the thought of nudity, men can at least open their legs wide to reduce the surface area of testicular contact with the crotch and increase exposure to the cooler temperature outside the body. Men do this because it feels more comfortable, but it feels more comfortable because cooler testicles are what men need.
When our legs are opened wide, men are not saying come and get it (though if a woman wants to come and get it, why not?). Rather we are merely doing our appointed job as males: attempting to generate healthy sperm to make healthy babies.