A new study from Harvard University found that men who smoke marijuana had significantly higher sperm counts than men who do not smoke marijuana. The findings were published last week in the journal Human Reproduction.
The researchers looked at 662 men at the Massachusetts General Hospital Fertility Center between the years 2000 and 2017. From the men enrolled in the study, 1,143 semen samples were collected. Of the enrolled participants, 365 men reported having ever smoked marijuana and 297 reported having never tried it.
The men who had smoked marijuana had significantly higher sperm concentrations with an average of 63 million sperm per milliliter of semen compared to non-smokers who had an average of 45 million sperm per milliliter of semen. There were no significant differences in sperm counts when comparing former marijuana smokers to current marijuana smokers.
The findings of the study took into account other variables that could affect sperm counts, such as age, abstinence time, smoking, consumption of coffee, alcohol, and cocaine.
The study also found that men who had ever smoked marijuana had higher testosterone levels than men who had never smoked marijuana. “With an increasing use of marijuana, there was a positive association with serum testosterone levels,” said lead researcher Jorge Chavarro, an associate professor of nutrition and epidemiology at Harvard University. He also stated, “We know that men with higher testosterone levels tend to engage in risk-taking behaviors. The higher your testosterone, the more likely you are to do risky stuff,” such as using recreational drugs.
So, at this point, we can’t say if it’s the marijuana that makes the sperm counts higher. It may be the already higher testosterone levels that cause the sperm counts in marijuana smokers to be higher.
“The unexpected findings from our study highlight that we know too little about the reproductive health effects of cannabis, and in fact, of the health effects in general, to make strong statements about the impact of cannabis on health, with the possible exception of mental health,” said Chavarro.
What this study shows us is that smoking marijuana may not necessarily be as detrimental to a man’s fertility, as was previously thought. We shouldn’t rush out and have males smoke marijuana though because although this study showed higher sperm counts in marijuana users, it did not examine whether or not marijuana use had an effect on the sperm quality.
We need to wait for larger and more extensive studies to be done on the relationship between cannabis use and reproductive health before we come to any real conclusions about it.