Harvard scientists made big news Tuesday as they published a study showing that smoking marijuana is linked to higher sperm and testosterone levels. In doing so, they pushed forward a nagging question in marijuana research: What is it cannabis doing to our sex lives?
It turns out that marijuana’s effects on human reproductive activity can been studied in a variety of different ways. It affect our libidos, sperm quality, condom use, and our ability to make good decisions in the bedroom. In short, pot and sex continue to fuel healthy scientific debate and study.
Here’s what weed researchers have discovered so far about mixing marijuana with your sex life.
5. Marijuana May Not Actually Be Bad For Sperm
Before the Harvard University researchers published their study in Human Reproduction this week, the majority of research on smoking weed and sperm count suggested that future dads should lay off the green. But the new research, conducted on 662 men who’d submitted 1,143 semen samples to a Massachusetts fertility clinic, showed that the men who had ever smoked weed had significantly higher sperm count and concentration than those who hadn’t. Furthermore, the ones who had “more intense use” of marijuana had higher blood levels of testosterone.
The results were unexpected, but not implausible. They might suggest that moderate exposure to marijuana really does lead the body’s endocannabinoid system to produce more sperm (while heavy use cancels this effect out), or they might simply be due to the fact that high-testosterone men are those that end up smoking weed in the first place. It’s too early to tell, but this unsettled space is one to watch.
4. Marijuana Users Have More Sex
There’s lots of anecdotal evidence that getting high makes people horny, but the 2017 Stanford University study showing that people who use marijuana have sex more frequently illustrated it in hard data.
Using self-reported data on sex frequency and marijuana use on about 51,000 people from the National Survey of Family Growth, the team showed that women who didn’t use marijuana had sex an average of six times in the four-week period preceding the survey, whereas those had used it every day had sex an average of 7.1 times. Meanwhile, men who didn’t use it had sex an average of 5.6 times, while male daily users had sex an average of 6.9 times (nice!). It’s unclear if marijuana use influenced all that sex-having.
“Usually, people assume the more frequently you smoke, the worse it could be when it came to sex, but in fact, we learned the opposite was true,” Dr. Michael Eisenberg, assistant professor of urology at Stanford University Medical Center, told CNN in 2018.
3. “Dual Use” of Weed and Booze Linked to Unprotected Sex in Teens
Not all the research spells such positive news for sex and weed. In 2018, a study published in The American Journal on Addiction, based on data from the CDC’s Youth Risk Behavior Survey, showed that the risk of unprotected sex for teens who got crossfaded — used marijuana and drank alcohol — rose by a factor of 1.71 for males on these “dual use” days and by a factor of 3.39 for females.
The findings are perhaps not that surprising — people make bad decisions that feel like good decisions while they’re inebriated — but they should also be interpreted with caution, since the teens in the survey were self-reporting on their drug/alcohol use from the past 90 days and didn’t necessarily say that inebriation led to or influenced their sexual behavior. Still, it’s not a terrible thing to be cautious about.
2. Marijuana Changes the Way Sperm Genes Are Expressed
While the study published Tuesday suggests sperm count and concentration rises as a result of marijuana smoking, it doesn’t say much about how that happens. The drug’s effect on the actual mechanics of our cells is still being investigated. In late December, however, a small study on the sperm DNA of men who used marijuana at least weekly in the six weeks prior to the survey showed that they had pronounced changes in their sperm genetic profile.
Specifically, marijuana use was associated with changes to the epigenetics of sperm DNA, which refers to modifications to DNA that aren’t connected to the sequence itself. “We do not yet know what the implications of this latter finding are,” senior author Scott Kollins, Ph.D., tells Inverse.
1. Marijuana Might Get People Laid Because It’s Illegal
There’s at least one study showing that using marijuana could lead to more sex, but not because of any inherent chemical property of the drug itself. In 2016, a small study published in the Archives of Sexual Behavior suggested that it’s the fact that marijuana is illegal that it’s so strongly associated with more hookups.
Since marijuana has to be used in a relatively private place, the team argued, the environment it forces people into could lead to something a little more intimate.
“If you get someone to come home with you to smoke weed,” lead author and New York University population health expert Joseph Palamar, Ph.D., told Inverse at the time, “there’s a way to facilitate getting a sexual connection, for better or for worse.”