While the pill has been considered the go-to birth control choice for decades, there’s a growing minority of women opting for the oldest technique in the book: the pull-out method.

If you take a casual poll of your hetero friends in their 20s and 30s, chances are you know at least a few women who, after years of using condoms and hormonal pills, are now opting out of formal birth control entirely. And because we all know the true measure of a trend is by its name, take this as evidence: millennials were dubbed “The Pullout Generation” by New York Magazine… all the way back in 2013. In my circle of friends, it has only grown in popularity since then.

To put it bluntly, the pull-out method is when a man withdraws during sex and doesn’t ejaculate inside of his female partner. If there’s no sperm swimming through your vaginal canal to meet the egg, the logic goes, you can’t get pregnant. And in fact, Planned Parenthood notes that the method, also known as withdrawal or coitus interruptus, is used by 35 million couples worldwide.

Of course, some of that may be due to lack of access to other birth control methods. But for women who are choosing it above every other option, there’s something else at play here. And for many, that something else is the desire to avoid condoms (which are deemed less pleasurable), synthetic hormones (hey, we already avoid them in our food), and the physical and emotional effects of taking the pill (nice to see you, weight gain and mood swings).

“All of my doctors think I’m crazy and try to get me to use an IUD or get on the pill, but I say no,” one 32 year old woman, who uses the pull-out method with her long-term partner, told me. “I just don’t really want the hormones or foreign objects in my body. My current partner prefers the pull out method, and I feel comfortable with him and I like it too, so that’s how we roll.”

But here’s the real question: does it work?

But here’s the real question: does it work? The short answer is, kind of. It’s worth remembering that no birth control method is 100% foolproof, although some get pretty damn close (only 1% of women who use birth control pills and less than 1% who use an IUD will get pregnant in a year if those methods are used correctly). When employed accurately, Planned Parenthood reports, 4% of women who opt for withdrawal will still become pregnant in a year. And if done incorrectly, that number jumps to 27%.

Here’s where that 27% comes in. Some doctors caution that pre-ejaculate (a fancy word for pre-cum) can accumulate just enough sperm in the urethra from a previous ejaculation to cause pregnancy. Men should urinate between ejaculations to help prevent this. Pregnancy is also possible if semen is spilled on the vulva, the external opening of the vagina. And all of this, obviously, is dependent on the man having enough control of his ejaculations that he can be sure to withdraw in time.

Another way to ensure efficacy involves the rhythm or fertility-awareness method, in which women closely track their ovulation and avoid sex or use a condom leading up to and during that time period, which lasts about seven days. You can only get pregnant if an egg is present for the sperm to fertilize. Of course, effectiveness of this method depends on the regularity of your cycle, and how accurately you can track it. These days, many women use period tracker apps, but a more reliable choice is to use an at-home ovulation test that you can pick up at any drugstore.

But when all is said and done, things can still go wrong. Another 30-year-old Brooklynite told me he used a combination of withdrawal and fertility tracking with his former partner for years. After he returned from a vacation, though, they accidentally timed his partner’s ovulation incorrectly, and she became pregnant. Also? He had thrown caution to the wind and failed to pull out in time.

“The likelihood of not withdrawing quickly enough is inevitable,” he says. “And even if you withdraw diligently, there’s still a huge chance that you’re off by a few days with timing ovulation. You’re up against huge limits, and you aren’t sure what those limits are until she’s actually pregnant.”

Now, that’s one person’s perspective — but it’s also a man’s perspective. Whether or not you feel comfortable using the pullout method relies heavily on how much you trust and understand your partner (incidentally, it’s suggested by health professionals to only use this method when you’re in a longterm relationship).

So what does an Ob/Gyn have to say about all of this? “[The pull-out method] has risks that are greater than a woman who really doesn’t want to get pregnant should take,” Hilda Hutcherson, M.D., professor of obstetrics and gynecology at Columbia University Medical Center, told SELF. “It’s always possible to ovulate when you’re not expecting it, especially when you’re young. It’s not 100 percent, so you’re still taking a chance.”

So in sum: no, withdrawal is not as reliable as taking the pill or having an IUD. (And keep in mind that none of these methods will protect you against STIs—only condoms can do that.) But contraception is, ultimately, an incredibly personal choice. As always, it’s best to talk to your gyno about your concerns, preferences, and goals and make the decision that’s right for you. That is, at least, until the male birth control pill finally hits the market.

Eva Medoff is a writer and editor in Brooklyn, NY. She enjoys making her own candles, cooking vegetarian meals, and adding to her overalls collection (five pairs and counting). You can follow her attempts to become the indie Martha Stewart (read: broke DIY queen) on Instagram @cityandfox, and check out more of her work on her website.