Yes, we are talking about penis size.
Last week the US Academy of Sciences published a peer reviewed paper based on a study of the attractiveness to young women of various images of naked men.
The abstract for the paper reads:
Compelling evidence from many animal taxa indicates that male genitalia are often under postcopulatory sexual selection for characteristics that increase a male’s relative fertilization success. There could, however, also be direct precopulatory female mate choice based on male genital traits. Before clothing, the nonretractable human penis would have been conspicuous to potential mates. This observation has generated suggestions that human penis size partly evolved because of female choice. Here we show, based upon female assessment of digitally projected life-size, computer-generated images, that penis size interacts with body shape and height to determine male sexual attractiveness. Positive linear selection was detected for penis size, but the marginal increase in attractiveness eventually declined with greater penis size (i.e., quadratic selection). Penis size had a stronger effect on attractiveness in taller men than in shorter men. There was a similar increase in the positive effect of penis size on attractiveness with a more masculine body shape (i.e., greater shoulder-to-hip ratio). Surprisingly, larger penis size and greater height had almost equivalent positive effects on male attractiveness. Our results support the hypothesis that female mate choice could have driven the evolution of larger penises in humans. More broadly, our results show that precopulatory sexual selection can play a role in the evolution of genital traits.
If you need help with that, what it is saying is:
- We already know that larger male genitalia are a good indication of how likely young are to survive – so evolution pushes towards larger genitalia;
- But now we have evidence that women prefer large genitalia also;
- That female choice probably contributed to humans having bigger penises than other primates;
- Very big penises are not any more attractive than big penises;
- The taller you are the more important it is to have a large penis (or alternatively, if you are short then a larger penis is not much help);
- If you are more muscular you can get away with a smaller penis.
Update: Here’s a handy measuring chart from the paper:
Me? I’m going to spend even more time down at the gym.
- Penis Size: Does it matter and why? [Greg Laden’s Blog] (scienceblogs.com)
- Study: Evolution May Have Driven Humans Towards Bigger Penis Sizes (dailytech.com)
- Penis Size Matters More to Men’s Attractiveness Than Previously Thought (blogs.discovermagazine.com)