THE other day, I got an email from a 21-year-old college senior about sex — or perhaps more correctly, about how ill equipped she was to talk about sex. The abstinence-only curriculum in her middle and high schools had taught her little more than “don’t,” and she’d told me that although her otherwise liberal parents would have been willing to answer any questions, it was pretty clear the topic made them even more uncomfortable than it made her.

So she had turned to pornography. “There’s a lot of problems with porn,” she wrote. “But it is kind of nice to be able to use it to gain some knowledge of sex.”

I wish I could say her sentiments were unusual, but I heard them repeatedly during the three years I spent interviewing young women in high school and college for a book on girls and sex. In fact, according to a survey of college students in Britain, 60 percent consult pornography, at least in part, as though it were an instruction manual, even as nearly three-quarters say that they know it is as realistic as pro wrestling. (Its depictions of women, meanwhile, are about as accurate as those of the “The Real Housewives” franchise.)

A 2014 study of 16- to 18-year-old heterosexuals — and can we just pause a moment to consider just how young that is? — published in a British medical journal found that it was mainly boys who pushed for “fifth base,” approaching it less as a form of intimacy with a partner (who they assumed would both need to be and could be coerced into it) than a competition with other boys. They expected girls to endure the act, which young women in the study consistently reported as painful. Both sexes blamed the girls themselves for the discomfort, calling them “naïve or flawed,” unable to “relax.”

According to Debby Herbenick, director of the Center for Sexual Health Promotion at Indiana University and one of the researchers on its sexual behavior survey, when anal sex is included, 70 percent of women report pain in their sexual encounters. Even when it’s not, about a third of young women experience pain, as opposed to about 5 percent of men. What’s more, according to Sara McClelland, a psychologist at the University of Michigan, college women are more likely than men to use their partner’s physical pleasure as the yardstick for their satisfaction, saying things like “If he’s sexually satisfied, then I’m sexually satisfied.” Men are more likely to measure satisfaction by their own orgasm.

Professor McClelland writes about sexuality as a matter of “intimate justice.” It touches on fundamental issues of gender inequality, economic disparity, violence, bodily integrity, physical and mental health, self-efficacy and power dynamics in our most personal relationships, whether they last two hours or 20 years. She asks us to consider: Who has the right to engage in sexual behavior? Who has the right to enjoy it? Who is the primary beneficiary of the experience? Who feels deserving? How does each partner define “good enough”? Those are thorny questions when looking at female sexuality at any age, but particularly when considering girls’ formative experiences.

Read the full article "When Did Porn Become Sex Ed?" at The New York Times.