As marijuana legalization spreads and stigma recedes, older narratives claiming that copulation and cannabis don’t mix are falling by the wayside. Today, marijuana lube products fill internet storefronts, and there’s no end to claims that weed enhances sex, despite research that draws far more nuanced conclusions. Though it’s unclear whether cannabis goods really make sex better, bigger-picture studies suggest that the combination of sex and marijuana will have major implications for demographics and public policy.

The advice that marijuana will help with sexual issues is the opposite of what people once believed, says Michael Eisenberg, a urologist at Stanford University. The common hypothesis was that marijuana would lead to poorer sexual function, and some studies do suggest that marijuana can disrupt the menstrual cycle, lower sperm quality, or make it harder to reach orgasm.

Passing medical marijuana laws led to higher birthrates

But there are plenty of testimonials from people who swear that cannabis lubricant prolongs orgasm and cannabis tampons will relieve period pain. “For many of the lubes, is it more hype or more true response?” asks gynecologist Melanie Bone. “The only way to know is to study it.” However, we have very few studies because it’s notoriously difficult to do research using marijuana. (For what it’s worth, weed lube creator Foria Pleasure is currently recruiting and paying for a study examining whether its suppository reduces period cramps.)

We don’t know who or under what circumstances these products might help, and even if they do work, it might be unclear why. For example, many weed lubes contain coconut oil, so how do we know that it’s cannabis and not the coconut oil that’s effective? Does using marijuana as lubricant really make it more effective than consuming it directly? The potential negative side effects are also unclear.

Bone, who frequently prescribes medical marijuana to women who have low libidos, anxiety, or difficulty orgasming, says that the sexual effect of marijuana can vary greatly. “It’s not like the more, the better,” she says. “Maybe some amount will relax you and make you more open to sensations and less inhibited with your body, but if you get super stoned, you’re not going to be able to concentrate.” Some of her patients have said that suppositories or weed lubricants are great; others say that they’re far too intense.

Though no hard evidence supports the sex-enhancing claims of these products, other research does suggest that marijuana, in general, can lead to more time in the sack. Eisenberg became interested in the link between marijuana and sex after male patients started asking whether cannabis would “affect function down there.” For a study published in the Journal of Sexual Medicine last year, he analyzed data from the National Survey of Family Growth, covering nearly 60,000 people, and found that people who consumed marijuana tended to have more sex. For example, women who consumed marijuana weekly had 34 percent more sex than those who didn’t; the number was 22 percent more for men.

Eisenberg acknowledges that the data is self-reported, which makes it less reliable. It’s also possible that the people who smoke marijuana are also the people who simply have more sex to begin with. “Still, the interesting thing about the study is that we also were able to look at all different demographic groups, based on race and ethnicity, marital status, and education level,” Eisenberg says. “And across all groups, you saw the same relationship, so it’s not like this association is being driven by one particular group.”

New research from Michele Baggio, an economist at the University of Connecticut, finds an even more striking pattern. For a working paper, recently posted to the National Bureau of Economic Research, Baggio, along with co-authors Alberto Chong and David Simon, analyzed three different datasets. They concluded that passing medical marijuana laws led to higher birthrates. Specifically, it increased the birthrate by approximately four births per quarter for every 10,000 women of childbearing age.

First, they found that when medical marijuana laws pass, it leads to more people smoking marijuana, including recreationally. Next, it turns out that consuming marijuana encourages riskier sexual practices, like buying and using fewer condoms, which leads to more births. This doesn’t mean that the medical hypothesis — that marijuana can cause sexual issues — is false. More likely, this is a case when behavior trumps biology. “While medical literature points to a possible negative effect of marijuana, this does not take into account how people behave and how that could shape the actual behavior of people,” Baggio says.

So even though marijuana probably makes it harder to ejaculate and makes it harder for sperm to reach the egg, those birthrate-lowering effects are negated by fewer people using protection while they’re high. (Other studies have found the same link between consuming marijuana and not using contraception.) It’s important to do this research so we know the potential unintended consequences as marijuana legalization spreads, Baggio says.

We need more research on the product claims of marijuana. But, even more importantly, we need studies like the ones that focus on birthrates or the one from last year that suggests that marijuana might lead to more aggression with romantic partners, at least in young couples. While scientists already have a head start at tracking down the side effects of marijuana products in people, side effects in populations remain more of a mystery.

“We need to start thinking about unintended consequences,” says Baggio.