For most people, sexual education covers only the basics: what happens to our bodies in puberty, how babies are made, and that having sex — particularly unprotected sex — put you at risk for getting sexually transmitted diseases (STDs). While sex ed aims to give useful information, there are plenty of signs the facts aren't getting through. "We take it for granted that people have the knowledge that they need," says Elissa Barr, associate professor of public health at the University of North Florida. "But the majority of them don't and that's been proven" by statistics about America's remarkably high pregnancy and STD rates. Here are some of the biggest myths and often-overlooked facts about sex, STDs, and getting pregnant.