A new study published in the journal Human Reproduction reveals that men who reported smoking cannabis had higher sperm counts than men who claimed to never have smoked, Live Science reports.
The findings contrast with previous studies that showed sperm count falls alongside cannabis use. Researchers theorize that the difference may be dependent upon dose and other factors.
Interestingly, those who have smoked in the past had higher sperm counts than those that had never smoked, the sperm counts of those that had smoked continue to rise — after they stopped smoking. Each year between the time of measurement and the time when the subject last smoked appeared to add additional percentage points of sperm count.
The study looked at 662 men who had had sperm samples taken during fertility testing with their partners. 55 percent of the subjects reported having used cannabis at some time in the past and 11 percent said they were current smokers. The remainder said they had never smoked. Those who reported having smoked cannabis had an average sperm count of 63 million sperm per milliliter, compared to 45 million per mL for those who had never smoked.
Also, only 5 percent of smokers had below average sperm counts, while 12 percent of those who had never smoked showed lower-than-normal counts.
Researchers acknowledged some issues with their data collection: for one, the study subjects were all being tested for fertility issues. Also, it’s been shown that men with higher testosterone as a whole will have higher sperm counts — and are also more likely to engage in “risky” behaviors like drug use.
More research is needed, the researchers suggested.