There’s a girl. Let’s call her Emily.

Emily is probably in her early 20s, but she might be as old as 35. She’s Internet savvy and college-educated; she lives in or near a city, works in an office, and votes Democratic. She has a boyfriend, a fiancé, or even a husband, and all her exes are men. She might have fooled around with women in college, strictly first-base stuff, on a dare or while drunk. But she’s never, as the wink-nudge Monty Python skit says, been with a lady.

Nevertheless, Emily is bisexual.

Or, rather, in the parlance of 2024, she identifies as bisexual—publicly, proudly, and often quite vehemently.

If you’re under the age of 40, chances are you know an Emily—or several, if you’re politically progressive and/or extremely online. They’re here, they’re queer, and they represent a seismic shift in how the next generation of young adults conceives of sex and sexual identity, at a moment when polling reveals that more than one in five adult members of Generation Z identify as L.G.B.T.Q.+.

It’s specifically the B in that increasingly unwieldy acronym that appears to be the locus of this transformation, driven in large part by a massive upswing in bisexuality among women under 30. According to a recent Gallup poll, more than 20 percent of Gen Z women identify as bi (for millennial women, that number is 9 percent), as do 6.9 percent of Gen Z men (as compared with 2.5 percent of male millennials). The reason for the largely female bisexual surge remains a topic of fierce debate. Many believe that greater social acceptance has simply led more people to come out of the closet. It was ever thus, in other words; we just didn’t know it.

But it’s not just attitudes that have changed. The entire concept of orientation—and the words we use to describe it—clearly means something different from what it used to. One 2016 study found that roughly one in five self-identified lesbian teens had recently slept with a male partner; a 2022 New York Times Styles-section piece featured a “queer couple” consisting of one husband and one “nonbinary wife.”

These days, the bar for entry to the rainbow tent is virtually nonexistent, although not everyone inside appreciates your pointing this out. One avowedly bisexual woman not only refused to be interviewed for this article but pointedly suggested that there was something intrusive, even creepy, about the fact that I was writing it at all. “Not gonna lie,” she wrote, “I’m kind of suspicious of cis het who are trying to source queer women to speak on a [sic] article about their interpretation of queerness.” I should add that she, like me, is white, millennial, and married to a man.

Clearly, we are in the throes of a new sexual revolution—except this one centers not on the practice of sex but on the principle of it. The eagerness of young people to adopt the L.G.B.T. label would have been an unthinkable state of affairs as recently as 20 years ago. Likewise, the defiant, even angry insistence that if you identify as queer, then you are no less gay than the folks who have been frequenting the bathhouse down the street since 1984.

Three years ago, in a since deleted tweet, the popular trans YouTuber ContraPoints noted the bewildering and seemingly contradictory nature of this new sexual paradigm. “Gen Z people are hard to figure out,” she wrote. “They’re like, ‘I’m an asexual slut who loves sex! You don’t have to be trans to be trans.Casual reminder that heterosexuality doesn’t make your gayness any less valid!’”

For those of us who went through puberty in the pre-Internet age, sexual orientation is inextricable from the embodied act of sex. But many Gen Z–ers reject this notion, which makes a certain sense when you consider that they are not only the least sexually active generation in modern history; they are also the first for whom social and sexual awakening was experienced primarily online.

We are in the throes of a new sexual revolution—except this one centers not on the practice of sex but on the principle of it.

In their world, sexual orientation need not concern itself with the sight, the smell, the raw physicality of another human body; it’s an abstraction, a menu consisting of foods you associate with sophistication but have never actually tasted. Under these circumstances, it becomes difficult to parse the difference between what you desire and what you want to be seen as affirming. As Phoebe Maltz Bovy, a culture writer currently at work on a book on female heterosexuality (and with whom I co-host a podcast), writes, “There’s a sort of ‘bisexuality’ that is almost an assertion of non-homophobia. Like, ‘I am not opposed to wanting the thing,’ which is different from… wanting the thing.”

So if sexual orientation no longer has anything to do with sex, what does it have to do with? “Vibes,” for one, but also politics. The aforementioned polling notes an overall increase in adults “identifying as lesbian, gay, bisexual, transgender, queer or some other sexual orientation besides heterosexual,” and it’s that last part—anything but straight!—that seems key to understanding this shift.

For young women in particular, identifying as queer is an effective shorthand for signaling that they believe the right things and support the right causes. At a moment when a commitment to inclusion is a requirement to remain a liberal in good standing—and when progressive spaces are roiled by debates over whether it’s transphobic for lesbians to refuse to date “women with penises”—calling yourself straight feels aggressive, exclusionary, even trad.

A bisexual label, on the other hand, renders you safe from scrutiny while conveniently making no demands upon how (or with whom) you have sex. As the writer Park MacDougald tweeted in response to the new polling, “‘Bisexual’ just means Democrat.”

And yet: as it happens, the same week that Gallup declared Gen Z the queerest generation in history, I was in Cancún, along with what seemed like the entire college-aged population of the United States. It was a rare opportunity to study the Zoomers at close range, and an informative one. For delicacy’s sake, I won’t go into exact detail about what happened every night in a hot tub that was visible from my hotel-room balcony, but suffice it to say that some of them have not gotten the memo.

Kat Rosenfield is the author of several books, including No One Will Miss Her