What even, evolution?

[FanndisTS]

Okay, so the length of the average vagina when aroused is four and a half inches, and the length of the average penis when aroused is about five and a half inches. Why??? Shouldn't penises be shorter than vaginas, to reduce chances of hitting the cervix and causing discomfort, making the female less likely to mate with the same male in the future? How did this happen, evolutionarily? I'd think that selective mating would lead to a population comprised of males with penises shorter than five inches...

[Sam W]

Hi Fanndis,

Full caveat: I am not an evolutionary biologist. But, I suppose part of the answer is that penis size was unlikely to be the primary trait someone was considering when choosing a mate (kind of how it's not the primary trait now), and that (especially way, way back when) pleasure may not have been the primary concern of humans when it came to reproduction.

[Jacob]

I guess this is maybe part of why average anatomical sizes of stuff (and some ideas of evolution) doesn't tell the full story. There are a lot of shapes and sizes that go together to make up that average, not to mention that people tend to have sex in lots of ways and positions. The idea of the length of a penis being fully inside the entire length of a vagina, for me doesn't really account for the people attached to those bits and pieces and there other body parts getting in the way. However as with all evolution things, the closer you look, the more complicated it gets, e.g. sometimes body parts evolve because of how they 'look' and some societies might find idealise bigger penises, other cultures might idealise smaller ones so evolution results in things that seem unexessary like peacock feathers. But there are even more factors than that.

Evolutionary biology is in the funny position of being something that seems simple for most people to grasp to but experts constantly prove is more than what it seems.