Chronic marijuana use negatively impacts male reproductive health, may decrease testicular function
OHSU study is the first to link daily use of edible THC with reduced testes size, lowered testosterone levels in nonhuman primates.
news.ohsu.edu
“Our analysis of the collected samples found that THC use was associated with significant adverse impacts to the animals’ reproductive hormones, including decreased levels of testosterone and severe testicular shrinkage. Specifically, we observed a greater than 50% decrease in testicular size,” said the study’s senior author Jamie Lo, M.D., M.C.R., associate professor of obstetrics and gynecology (perinatology and maternal-fetal medicine), OHSU School of Medicine, and Division of Reproductive & Developmental Sciences, Oregon National Primate Research Center at OHSU. “Unfortunately, these effects appeared to worsen as the THC dose was increased, suggesting a possible dose-dependent effect.”
The same group also found similar negative impacts in female reproductive health from a previous study:
Chronic marijuana use alters female reproductive system, may impact successful conception
OHSU study finds association between THC, ovulatory disfunction in nonhuman primates.
news.ohsu.edu
“In just a short time period, we observed irregularity in the animals’ reproductive cycles,” said the study’s lead author Jamie Lo, M.D., MCR, associate professor of obstetrics and gynecology (perinatology and maternal-fetal medicine), OHSU School of Medicine, and Division of Reproductive & Developmental Sciences, Oregon National Primate Research Center. “Overall, menstrual periods were longer in duration and levels of follicle stimulating hormone, one of the critical regulators for the body’s reproductive function, increased. These factors suggest the strong potential for reproductive system dysfunction that, in turn, may impact the ability to become pregnant.”
These were edibles so this wouldn't be due to estrogenic effects of smoke/burned plant matter. Also it looks like this was specifically THC. I believe there have been studies showing positive effects (or non-negative effects) on testosterone/androgens with other cannabinoids, including CBD. Perhaps the combination can counteract the negative effects of pure THC.