Heads Up, Dudes: You Have Nipples Because Every Single One of You Used …

Okay, fine, some people prefer to call this early in-utero period as one without sex, but if you want to be technical about it, the early stages embryonic development are courtesy of the X chromosome. Granted, if an embryo has a Y chromosome, it's there from the moment of conception — but Mr. Y doesn't lift a finger… » 1/10/13 12:05pm 1/10/13 12:05pm