A number of recent studies have already shown that cannabis has the potential to lower sperm count, but recently, another new study was conducted and the research discovered that the drug actually causes changes to the sperm itself — which might potentially lead to the user experiencing implications for the health of a potential child.
The study was first published in the journal Epigenetic’s, where experienced scientists at Duke University conducted an array of tests where they compared the sperm of two groups of rats, those who had been given tetrahydrocannabinol (THC), the psychoactive ingredient in cannabis, and those who had not been given the THC. The researchers then compared the sperm of 24 human men who smoked marijuana weekly against that of a control group who used marijuana less than 10 times overall in their life, and not at all in the past 12 months. In both cases, in rats and humans, the marijuana changed how their genes work in sperm cells.
Susan Kay Murphy, a professor of Gynaecology at Duke University and Co-author of the study explained the process in comparison to DNA, saying that readers should “think of their DNA as a list of instructions for making proteins, and genes as small subsets of that list.” Murphy believes that our body has little chemical tags called methyl groups that get added to the DNA at specific regions, where these particular chemicals don’t mutate the genes themselves, but they do affect how they’re used, like deciding which instructions are followed and which aren’t.
In both rats and humans, the study found that the cannabis affected many different genes which are involved in two different ways. While one is extremely important for organs to reach full size, the other one plays a role in cancer and suppressing tumors. “That just blows my mind,” says Murphy. “How do you even reconcile that, biologically, an entire pathway is going to be affected by these changes?”
While nerve-wracking, the sample size was small and the concentration of THC was not controlled in the human subjects. Even with this being said, the scientists did note more changes in the sperm was associated with higher levels of THC found in the subjects’ urine.
Additionally, Murphy clearly expressed that this particular study in itself is a pilot study that was originally intended to see if cannabis even has any effect of this kind to begin with on sperm. The sample size is small, and they didn’t control for the concentration of THC the human recruits smoked. The scientists did, however, agree that they accurately pin-pointed a measurement of THC in the urine and noted that more THC in the urine correlated with more changes.
“This is a smaller study, but with concerning implications,” says Bobby Najari, a urologist at NYU Langone who was not involved in the study. Najari already counsels men who use marijuana regularly to cut back because of the effect on sperm count. “I think one of the important positive things about research like this is that it may further motivate men to change their health,” he adds. “It’s one thing to talk about sperm count, another when you’re talking about the potential health of the child.”
While there’s large evidence to show the degree that side effects may have in the future, both Najari and Murphy stress that much more future research would need to be done in order to 100% sign off on the matter. Fortunately, the Duke University team is reportedly already working on follow-up studies to discover more detail and uncover marijuana fully.
“I want to be very careful to not have the results turned into something that they’re not,” says Murphy. “It’s not intended to scare people. Our whole objective is to learn more about biology and what effects there might be.” she explained.