CannabizDaily has recently reported about a very small study in South Africa that suggests that the use of cannabis by men can negatively alter their sperm and significantly affect their fertility. The study recommends that men who are trying to conceive with their partners put the habit of smoking pot on hold.
A separate — and bigger — study seems to have contradictory findings.
The new study unexpectedly linked smoking pot to greater fertility in men. The result came as a surprise to scientists who had expected cannabis to have a detrimental effect on sperm count and on male fertility in general.
The researchers collected over 1,100 semen samples between 2000 to 2017 from more than 600 men who were attending a fertility clinic with their partners. The men had an average age of 36, and most of them are white and college educated. All of them were seeking help from a fertility clinic to conceive.
The participants were asked to fill in a questionnaire detailing their history of marijuana consumption. More than half of the men admitted to having smoked pot at some point. Of these, 44 percent said that they had used the drug in the past while 11 percent considered themselves as current users.
The researchers measured the sperm counts on the semen samples from participants. It turned out that the participants who admitted ever taking cannabis have higher sperm counts than those who do not use the drug.
More specifically, the analysis of the semen samples showed that the participants who have smoked cannabis had sperm concentrations averaging 62.7 million sperm per milliliter. Meanwhile, those who had never smoked pot had an average sperm count of 45.4 million/mL.
The researchers also noted that only 5 percent of cannabis users had below 15 million/mL sperm counts. This number is the threshold for normal sperm levels according to the World Health Organization. Among men who never smoked a joint, this number is 12 percent.
Additionally, greater use of pot was linked to higher levels of the male hormone testosterone.
However, the authors of the study, as well as other experts, were quick to stress out that this finding does not necessarily mean that smoking weed increases a man’s chances of fatherhood.
They said there could be a non-causal explanation for the association, such as testosterone’s effect on risk-taking behavior like smoking pot and on sperm count.
According to lead researcher Dr. Jorge Chavarro of the Harvard T.H. Chan School of Public Health, their unexpected findings underscore how little people know about the effects of marijuana on reproductive health, and on health in general.
He said that their findings must be interpreted with caution. Their study, he added, emphasizes the need for further studies on the effects of cannabis consumption on health.
The researchers noted that it was possible that low-level cannabis exposure might benefit the production of sperm in some way. The endocannabinoid system in the brain, which is targetted by cannabis, is known to play a role in regulating fertility.
The association could also have nothing to do with the effects of smoking pot.
Dr. Feiby Nassan explained that an equally plausible interpretation is that their findings could reflect the fact that males with higher testosterone levels are more likely to engage in smoking pot and other risk-seeking behaviors.