Evolution of the Penis and Testicles

Interesting article. Although, it doesn't quite correlate with the literature in evolutionary biology. Primate sexual selection on penis morphology tends to focus on "complexity" of the penis. Males of polygamous species tend to have more complex penis morphologies and larger testicles that would attract multiple females. Males of more monogamous species (like humans) tend to have fairly simple penis morphologies and smaller testicles because the focus is on attracting only a few females and retaining them.

Personally, I think men are much more concerned with penis size than women are. The whole penis envy thing is a myth. Women tend to care more about overall skill and willingness to learn what she likes.