If cannabis made you less fertile, there are some who would be pleased, not wishing to be burdened with kids. But it would threaten the continuation of the species, which is ever so slightly A Bad Thing.
So there was this study …
In 2014, the world’s largest study of lifestyle and sperm quality found that taking cannabis doubled the risk of men of less than 30 years of age producing abnormal sperm, making them significantly less fertile. Drinking, mumps, obesity and smoking were in the clear. Tighter underwear was not found to have this effect in this study, but others found that it also equalled lower fertility because less sperm is produced at a higher temperature.
The sperm of 318 men at 14 fertility clinics was examined. The study was published in the journal Human Reproduction. Quite why younger men would be less fertile is unknown, but Dr Allan Pacey of Sheffield University, who led the study, suggested it was because younger men smoked more. He added that if someone stopped smoking cannabis, no immediate improvement would be apparent – it would take three months.
And another one!
Another study, this time by the University of Copenhagen and published in the American Journal of Epidemiology, covered 1,215 men from the ages of 18 to 28 who were being evaluated for fitness for military service and found that smoking dope at least once a week reduced sperm counts by about a third, which rose to 55 percent if other drugs, such as coke or ecstasy, were also taken. Tina Kold Jensen, the lead author, described the effect of cannabis as “quite a lot.” While her team tried to account for it, the problem might be that men who consumed marijuana regularly have generally unhealthier lifestyles, featuring more alcohol, caffeine and cigarettes.
Another study to find cannabis making men less fertile was by the University of Buffalo School of Medicine and Biomedical Sciences and was announced at a meeting of the American Society of Reproductive Medicine in 2003. Lani J Burkman, PhD, who led the study, commented that “Marijuana-smoking men’s sperm are hyper. They are way out there…. Sperm should be quiet at first.”
Dr Burkman acknowledged that many men who smoked marijuana had fathered children, but if their fertility was borderline, cannabis could “push them over the edge.”
Cannabis does, certainly, cause men to be less fertile. Sperm must swim all the way up the vaginal canal, where an egg awaits. Usually, those little devils don’t start swimming immediately, instead going with the flow of semen. Delta-9-tetrahydrocannabinol, known as THC, the fun bit of cannabis, gets them swimming immediately, tiring them out. Cannabis also results in a lower sperm count to begin with. Worse yet, sperm must release certain enzymes to penetrate an egg’s wall, and THC impedes this by 30 percent. In this case, the smoking could have been undertaken by either the man or the woman.
Women should also worry
Women also have cause for concern: cannabis significantly lowers egg quality. A study by Mueller et al in 1990 found that abnormal ovulation patterns resulted from cannabis use, for instance delayed ovulation. Other studies discovered that regular pot smokers were at marginally higher risk of anovulatory cycles, where there is no egg at all. The reason is believed to be that cannabis lowers production of luteinising hormone, which stimulates ovulation.