Scientists: Why penis size does matter

Women prefer big penises, thunders a new study published this week in the Proceedings of the National Academy of Sciences, or PNAS. (Say it out loud.) Researchers had 105 heterosexual Australian women (average age: 26) rate 49 computer-generated nude images of male bodies. Their task? To rate each CGI-bro on a scale of 1 to 7, with each figure controlled for three different traits: Height, shoulder-hip ratio, and flaccid penis size.

Here's the sexy stuff the women were asked to look at:

After controlling for the other two variables (height and shoulder-hip ratio), Australian National University researchers were able to confirm their suspicions: Bigger is better, at least according to this group of heterosexual Australian women asked to rate these ghostly, faceless renderings of the male body. "As you increase penis size, the amount of attractiveness scores gets bigger," post-doctoral researcher Brian Mautz tells NBC News. However, the women's attraction to flaccid penises petered out at 3 inches; after that, say researchers, the attractiveness still increased, albeit in much tinier increments.

But package size wasn't the only indicator of attraction: Height was also crucial. Unsurprisingly, "tall guys with really large penises ended up being most attractive relative to other figures," says Mautz, which inadvertently explains the media's recent fascination with a certain part of actor Jon Hamm's anatomy.

Back to the science, though: The biologists behind the study theorized that penis-size may have played a significant role in human evolutionary history. "It's not totally clear why women prefer bigger penises," explains National Geographic, "but studies have shown that women prefer larger sizes because they can increase sexual satisfaction." Oh?

Oh. Thank goodness for clothes, then. And having a face.