A new study in reproductive physiology at the University at Buffalo is the first to assess marijuana's effects on specific swimming behaviour 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.

Results of the study were presented today (Oct. 13, 2003) at the annual meeting of the American Society of Reproductive Medicine in San Antonio.

"The bottom line is, the active ingredients in marijuana are doing something to sperm, and the numbers are in the direction toward infertility," said Lani J. Burkman, Ph.D., lead author on the study. Burkman is assistant professor of gynecology/obstetrics and urology and head of the Section on Andrology in the UB School of Medicine and Biomedical Sciences. UB's andrology laboratory also carries out sophisticated diagnosis for infertile couples.

"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."...