Let's Get Upright

For class, I read an article entitled "What Have We Done to Deserve This?" by Peter Lehman. Though entirely about naked men, it seems tame in comparison to last week's naked men experience. From the article, I learned a lot about the penis, including this tidbit:

Sheets-Johnstone argues that evolutionary scientists have not understood the crucial role of the penis in accounting for how hominids became bipedal. Her argument is that in a quadrupedal state neither the sight nor the size of the penis is of great importance; on the contrary, the female pudenda, not the penis, is the sight of significance. Nonhominid, quadrupedal sexual behavior revolves around posterior sexual presenting, and therefore changes in the size, shape, and color of the pudenda are important visual signals to males. The penis remains largely invisible. Only with the shift to upright posture does the display of the penis become important, and such display is constant with bipedality.

In other words, if it weren't for men wanting to show off their cocks, we'd still be crawling. The next time you see a shady man exposing himself in an alley, don't scream and call the police: thank him for your ability to walk.