It was already known that cigarette smoking could decrease fertility rare for both men and women, but the same impact was not yet determined on smoking marijuana. Now, a recent study has found a surprising effect of smoking marijuana on sperm cells.
Previous studies suggested marijuana could also have an adverse effect on sperm production. Harvard researchers also expected they would find a similar result in their new study, which was published in the Human Reproduction journal. However, their finding was not what they expected.
Researchers found men who smoke marijuana had higher sperm concentrations compared to non-users. To confirm their findings, the team examined the data more than once to make sure there's no mistake in their research.
According to Dr. Jorge Chavarro, the co-author of the study and professor at the Harvard T.H. Chan School of Public Health, they spent two months redoing the study to confirm there's no error in the data and they were really surprised with the result
In the study, researchers tested semen samples from 662 men, wherein 365 of them smoked marijuana at least once in their life. The subset had higher sperm concentrations and counts compared to those who never smoke marijuana in their lives. In addition, those who frequently smoked have higher testosterone levels than those who rarely do it.
Feiby Nassan, the lead author of the study and a postdoctoral research fellow at Harvard, explained their finding has two different interpretations. First, low levels of marijuana use could benefit sperm production due to its effect on the endocannabinoid system - plays an important role in fertility. But, the benefits lost with higher levels of marijuana consumption.
Researchers noted their findings do not mean men should start smoking marijuana to boost their fertility. The team said it's not yet understood if marijuana use had such effect or if men with higher testosterone were more likely to engage in risky behaviors - like the use of cannabis. Semen quality isn't also an accurate indicator of fertility, the authors added.
And while there had been a recent rise in the legalization and recreational use of marijuana in the United States, the study was conducted when cannabis was illegal in Massachusetts. That means some participants chose to lie about the extent of use or to hide their drug use. Still, the study indicates there's a lot to discover about the effects of cannabis on the human body, either harmful or beneficial.
