When Is It RAPE?

Be careful of strangers and hurry home, says a mother to her daughter, knowing that the world is a frightful place but not wishing to swaddle a child in fear. Girls grow up scarred by caution and enter adulthood eager to shake free of their parents' worst nightmares. They still know to be wary of strangers. What they don't know is whether they have more to fear from their friends.

Most women who get raped are raped by people they already know -- like the boy in biology class, or the guy in the office down the hall, or their friend's...