Atomic Nerds

Scratching about for content while fixing up the place to host guests (no content 4 u tomorrow, sorry), a friend asked me in the spirit of helpfulness whether the fixation on penis size men and women alike in many cultures seem to have is likely to be cultural, or genetic. So okay, an easy enough question to answer.

In terms of aiding the evolutionary success of its owner, a phallus has one purpose: deliver sperm to egg. This can either be a low-demand task that you don’t necessarily need any intromittent organ for at all- see most birds, fish, and many reptiles- or it can be a towering chore that requires the penile equivalent of advanced technology (elephants, rhinos). Whether it can move on its own, impress rivals, or otherwise do tricks are all highly secondary to this purpose, unless you are a female hyena, in which case zoologists have a long list of questions to ask you.

Most primates have relatively small penises in relation to their body size, with the most notable exception being humans. Why we ARE the exception has likely the most to do with our unique bipedal posture; a critter that locomotes on its knuckles, or swings about in trees, simply has an easier angle of penetration than we do. Anyone who has had heterosexual intercourse probably remembers the bit no one tells you about, which is that penetration requires more than just “lie on top of girl, thrust”.

In order to accomplish the task at hand, the penis needs to be big enough to penetrate far enough to give the sperm a fighting chance at reaching the end of their swim, and that big only. More is not necessarily better for fertilization purposes- too girthy and it simply may not fit (locker-room joking aside, this can be an actual problem for anatomically mismatched couples), too long and he may bang into the cervix, which can be very painful for the woman and is not mood-enhancing. Correspondingly, the average human penis is just about as big around and as long as the average human vagina is broad and deep- and just as there is some direct selective pressure on the human penis getting too small, there is a direct upper limit on how much larger the vagina can get- we’re already seriously pushing against the limits for what kind of opening we can fit in our pelvises without compromising the owner’s ability to walk and run, and the dangers of childbirth for mothers relative to other species show it.

In strict terms of fertilization success, bigger is not better, average is exactly best. If our cultural patterns don’t reflect that, it may be a strong hint that cultural patterns are extremely unreliable reflectors of directly linked biological fitness benefits.

So why the cultural patterns, which are admittedly common and widespread? Probably because the penis is a really obvious and “standout” difference between men and women, and because cultures in general tend to find things to hang virility off of and display it. (Okay I promise I’ll stop with the bad puns now.) There’s also the idea that bigger really does make sex better, which perhaps a majority of men, a smaller majority of virginal women, and a minority of experienced women who enjoy the sensation a lot all share- which goes less to “we are attracted to features that will directly increase our fitness” than it does to “we are attracted to features we think will gratify us sexually and emotionally and fitness is a payoff afterward”.

In any case, “culture, imagined virility display” is a much more sensible answer to why men are so much more interested in measuring penises than women tend to be.

Posted my furious genitals, Science: we'll fuck you up |