Do Pierce and Courtney understand sexually transmitted diseases? Courtney says they've had presentations in school about them. "Quite a few times, from sixth grade till now," Pierce says.

Dr. Berman says that's good news. "For the past eight years at least, most schools—if they do have sex education—it's abstinence-only education," she says. "They teach you about sexually transmitted diseases and pregnancy, but they don't necessarily teach you about prevention."