I was watching something on the science channel a few weeks ago that enlightened me as to some stuff, one is about why I have nipples. Apparently (and pardon me if you already know this) all human babies default to female. Six weeks(ish) into the preganancy the introduction (or lack) of some gene makes the baby into a male, or leave it alone respectively. Apparently nipples form before 6 weeks, so all humans get nipples. I thought that was interesting and thought I'd share if you didn't already know that. Please, knowledgable people correct me if I got it wrong.