Men who smoke marijuana frequently have significantly less seminal fluid, a lower total sperm count and their sperm behave abnormally, all of which may affect fertility adversely, a new study in reproductive physiology at the University at Buffalo has shown. This study is the first to assess marijuana's effects on specific swimming behavior of sperm from marijuana smokers and to compare the results with sperm from men with confirmed fertility. Marijuana contains the cannabinoid drug THC (tetrahydrocannabinol), which is its primary psychoactive chemical, as well as other cannabinoids.
"We don't know exactly what is happening to change sperm functioning," said Burkman, "but we think it is one of two things: THC may be causing improper timing of sperm function by direct stimulation, or it may be bypassing natural inhibition mechanisms. Whatever the cause, the sperm are swimming too fast too early."