Why is the penis shaped like that, anyway? I talk to Jesse Bering about that and other questions he answers from an evolutionary perspective in his new book Why Is the Penis Shaped Like That?: And Other Reflections on Being Human. I also ask him about the contents of male ejaculate, female orgasms, and whether evolutionary psychology is really trustworthy. Jesse contributes to scientificamerican.com, Slate, and das Magazin. His book tour brought him to Capitol Hill Seattle and our studio.