According to an American study published in Human Reproduction, men who have already used cannabis would be more fertile than others.
Harvard researchers from the Chan School of Public Health have indeed found a higher concentration of sperm in people who had already smoked cannabis compared to those who had never done so.
To draw these conclusions, the scientists collected 1162 sperm samples between 2000 and 2017, from 662 pairs and an average of 36 years old. Of these, 317 participants had taken a blood sample for researchers to analyze their reproductive hormone levels.
The participants, who had all been to the clinic after experiencing a child with their partner, completed a questionnaire about their use of cannabis. In particular they were asked whether they had smoked more than two joints in their lives and that they are still smoking at the moment.
Higher sperm concentration for smokers
And there, surprise. Although the researchers expected a relationship between cannabis use and the sperm quality of the participants, the opposite effect appeared. Men who smoked cannabis had a concentration of 62.7 million spermatozoa per milliliter, compared with 45.4 million sperm per milliliter of sperm for men who were not affected by any absorption of the substance.
On the other hand, the sperm of former cannabis smokers and those who still smoked at the time of the study showed no significant difference.
Higher testosterone levels for heavy smokers
With regard to blood samples, they made it possible to emphasize that the largest smokers of marijuana had higher testosterone levels on average.
For Feiby Nassan, the lead author of the study, "(the) results went against the assumptions that (they) initially had (have)". However, they correspond to two interpretations. "The first is that low cannabis use may be beneficial for seed production because of the effects on the endocannabinoid system, which is known to play a role in fertility, but that these benefits are eradicated by consumption – more important cannabis," says the researcher. . "The other equally plausible interpretation is that our findings may reflect the fact that men with higher testosterone levels more often exhibit risky behaviors, such as smoking cannabis," Feiby adds. Nassan.
Underreporting of participants?
However, scientists have responded with caution when interpreting these findings, including the fact that the study may have been distorted by sub-reporting by participants about their actual cannabis use.
They add that previous studies, which suggested that this drug could have adverse effects on fertility, were mainly on animals and were targeted at low-risk men. "These unexpected results underline our ignorance about the effects of cannabis on reproductive health, as well as its effects on overall health," says research author Jorge Chavarro. And to conclude: "Our results must be interpreted with caution, but they emphasize the need to have a deeper interest in the effects of cannabis use on health".