Hookup culture is a hot topic these days. Some see it as a delightful grab bag of late-night calls, drunken texting and too much wine between more-than-friends; others see it as the downfall of Western Civilization.

But hookup culture isn’t new, no matter how much your grandparents want you to believe you’re single-handedly destroying the United States of America. Millennials by no means created “hookup culture.” The 1920s had “the flapper lifestyle,” the 1960s had “free love” and the 1970s had too much of everything. Millennials just made casual sex more efficient with apps, Tinder specifically, and a generation took up residence in the grayscale dreamscape of “maybe we are, maybe we aren’t.”

As Jon Birger, author of the book DATE-ONOMICS: How Dating Became a Lopsided Numbers Game, points out in his brilliant Washington Post piece, today’s hookup culture actually has a very similar setup to the Roaring ‘20s and their—ahem—"petting parties.“

The case then, as it is now, is that the game of running game is totally, extremely, definitely, whole-heartedly in the men’s favor. The reason is just super different.

See, what happened in the 1920s is that World War I caused a shortage of eligible bachelors, so, once the horrifying Great War came to a close, the Jazz Age that followed raged wild in what essentially became the Land of Women.

But what’s going on now isn’t war. It’s college.

College-educated straight men are cleaning up in the college and post-college dating scene simply because the ratio is so uneven. By how much? A lot, argues Birger. Some 34 percent more women than men graduated college in 2012, and the gap’s expected to grow to 47 percent by 2023, according to the U.S. Department of Education. These higher-educated dudes are just kicking back on the supremely unbalanced scale, waiting for the women to slide to them, with or without tech.

And therein lies the problem, writes Birger.

Of course, these lopsided numbers might not matter if young, college-educated women become more willing to date — and, eventually, marry — across socioeconomic lines. But according to separate research by University of Pennsylvania economist Jeremy Greenwood and by UCLA sociologists Christine Schwartz and Robert Mare, educational intermarriage is less common today than at any point over the past half century.

Read Birger’s piece in full here.