Back in the day, you’d go to a party, someone would take out a plastic bag, you’d take a big sniff of what was inside, and then let the next person have a go.

Similar parties are still being held today. But while the party animals of the ‘80s were hoovering the fruit of the Andes, today’s sniffers are hitting the Fruit of the Looms.

W— you may be asking yourself —TF?

I’ll tell you WTF—it’s a pheromone party. Yes, pheromone parties are a “thing” now.

This is how it works: you sleep in a T-shirt for several nights, stick the shirt in a freezer bag with a colored card—blue if you’re a boy, pink if you’re a girl—that’s numbered for identification. At the party you toss your bag on a table with everyone else’s and party-goers take turns sniffing them.

Still with me?

If a sniffer finds one he or she likes, a photographer snaps a picture of them holding the bag and projects it onto a wall so the shirt’s owner can step up and meet his or hers odor admirer.

People seem to prefer the odors of those whose genetic makeup is different—but not radically so—from their own. Makes sense to me; I know I would rather date someone with two X-chromosomes—preferably one with money who’s also a soccer fan.

While this smacks of pseudoscience—and possibly borders on underwear fetishism—it may have its roots in fact. Serious research, similar in methodology to the T-shirt party, suggests that our smell preferences may be nature’s way of preventing inbreeding.

According to Martha McClintock, founder of the Institute for Mind and Biology at the University of Chicago, “Humans can pick up this incredibly small chemical difference with their noses.” Her research has shown that people prefer different human scents and that whose they prefer is dictated by a set of genes that influence our immune response.

Not surprisingly, sniffers turned up their noses at bags that smelled like sweat or old people, but took second hits of fragrances they liked. One participant called the sniffing thing “an icebreaker” for meeting others; to me, if you’re too shy to say hello but comfortable sniffing a total stranger’s sweaty T-shirt, shyness is probably not your biggest dating roadblock.

Pheromone party fans say that the gatherings take romance back to its most primal beginnings. OK, to me, primal is not sniffing a sweaty T-shirt; primal is doing what my dog does when she meets another dog, and I’m sure I don’t want to do that—especially in a party setting.

So if I had to choose, in terms of swapping pheromones, maybe the sweaty T-shirt thing isn’t such a bad option.