Despite the dreams of social conservatives, few teens actually practice abstinence. Nearly 60 percent of students have sex before they graduate from high school , according to some surveys. Many do so without any instruction from parents or schools on condoms, infections or consent.

Perhaps that’s why one in four American women will become pregnant by the time they turn 20.

Or why a quarter of all new cases of sexually transmitted infections occur in teenagers — and the number of S.T.I.s has been at all-time highs.

Or why only 41 percent of American women have described their first sexual experience as wanted.

When we refuse to teach students about sex, we don’t stop sex — we just make it more dangerous. And it’s not just because of S.T.I.s.

Kids who lack information and ownership over their bodies are more likely to be taken advantage of. When children are taught that all premarital sex is negative , it’s harder for them to fight, or report, abuse or coercion.

Abstinence education negates the possibility of consent. When I was a teen, I was taught that men would try to get sex from me, and that my job was to say no. That made me feel as if the coercion and violations that happened to me were my fault. All sexual acts are equally wrong, so if a boy went too far on a date with me, it was my fault for letting him touch me at all.

Keeping children in the dark allows predators to set the narrative. They count on the culture of silence and the sense of shame. When virginity is prized as the highest honor, those who are assaulted can feel even more worthless — and may avoid reporting abusive or predatory behavior out of shame and confusion.

For L.G.B.T.Q. children, things can be even more bleak. A lack of inclusive sex education contributes to feelings of isolation and shame, while enabling bullies. L.G.B.T.Q. kids have even fewer resources, and face more drastic consequences — from physical abuse to homelessness — when they attempt to report assaults.