In 2002, 14-year-old Elizabeth Smart was abducted from her Salt Lake City home, held captive in the mountains, and raped repeatedly for nine months.* Since her escape, she has emerged as an advocate for human trafficking victims—and recently, a critic of abstinence-only sex education. When Smart spoke at a Johns Hopkins University panel last week, she explained one of the factors deterring her from escaping her attacker: She felt so worthless after being raped that she felt unfit to return to her society, which had communicated some hard and fast rules about premarital sexual contact.

“I remember in school one time, I had a teacher who was talking about abstinence,” Smart told the panel. “And she said, ‘Imagine you’re a stick of gum. When you engage in sex, that’s like getting chewed. And if you do that lots of times, you’re going to become an old piece of gum, and who is going to want you after that?’ Well, that’s terrible. No one should ever say that. But for me, I thought, ‘I’m that chewed-up piece of gum.’ Nobody re-chews a piece of gum. You throw it away. And that’s how easy it is to feel you no longer have worth. Your life no longer has value.”

As Jessica Valenti points out, the chewing gum analogy is a typical tactic employed by abstinence-only advocates to try to scare teenagers away from having sex. And while stunts like those are often delivered to coed groups, the messaging falls harder on girls: If one person is the gum, the other person chews. It’s difficult to add a rape exemption to that kind of visual. In the case that you’re abducted, does God lend you a fresh stick?

In the sex ed wars, we spend a lot of time crunching statistics to determine whether abstinence-only education is effective in encouraging teenagers to delay sex. We spend less time discussing its effectiveness in making teenagers feel like worthless members of society when they do decide to have sex—or, in the case of too many teenagers, when they are assaulted against their will. Forty-four percent of rape victims, like Smart, are under the age of 18 when they’re assaulted. “The best thing we can do is educate young people as young as we can reach them,” Smart said later. Survivors of rape and trafficking, she said, need to be “given permission to fight back,” and that requires them “to know you are of value.” Teachers “can’t start early enough.”

As Smart’s story shows, administering broad sexual shaming to children can have disastrous effects for victims of assault. The same goes for all of the other “tips” that put the onus on the victim to prevent rape. When we instruct teenagers to dress modestly, abstain from alcohol, never go out alone, and certainly never engage in sex, we’re not actually helping them prevent rape—but we are telling them that when they are victimized, they are partially to blame. Sex educators can’t equip children to escape horrific crimes like the ones committed against Elizabeth Smart. But they can help build a society that refuses to compound the psychological effects of those crimes by shaming victims before the abductor even breaks in.

Correction, May 7, 2013: This post originally stated the Elizabeth Smart was abducted in 2004. She was abducted in 2002.