When I headed off to university back in the Stone Age, girls were still afraid of being called sluts. By the time I graduated, there was a worse label – “unliberated.” It applied to girls who didn’t have sex. And no one wanted to be that.

Sexual liberation – the idea that women are entitled to the same sexual agency and opportunities as men – is at the heart of feminism. It’s great in theory. But for young women, it can be a disaster.

On many campuses today, hookup culture is the norm – especially for women who identify as feminists. Hookup culture decouples sex from commitment. It is thought to be practical as well as fun. It allows women to pursue their own interests and academic careers without the time-consuming burden of messy emotional entanglements.

There’s just one problem. It makes them utterly miserable.

“The truth is that, for many women, there’s nothing liberating about emotionless, non-committal sex,” writes Leah Fessler, who should know. As a student at Middlebury College, an elite liberal-arts school in Vermont, she was like a lot of high-achieving girls – cheery and successful on the outside, an emotional mess within. When she did some research, she discovered that her feelings were virtually universal among the campus women, and also shared by many men.

Ms. Fessler’s unsparing description of the sex lives of young feminists (Most Women Don’t Enjoy Hookup Culture, published in Quartz) is bleak. In hookup culture, commitment is seen as not only unnecessary but uncool. You can sleep with a guy for months, but God forbid you should be seen having lunch together. “Per unspoken social code, neither party is permitted emotional involvement, commitment, or vulnerability,” she writes. Young women are expected to ask for sex. But the one thing they can’t ask for is intimacy.