Marijuana smoking damages sperm

http://www.medicalnewstoday.com/articles/4482.php
Men who smoke marijuana frequently damage their fertility in several different ways, research suggests.

Scientists at Buffalo University found regular smokers had significantly less seminal fluid, and a lower sperm count.

Their sperm were also more likely to swim too fast too early, leading to burn-out before they reach the egg.

Lead researcher Dr Lani Burkman said: 'The bottom line is, the active ingredients in marijuana are doing something to sperm.'

Marijuana contains several chemicals known to have an impact on human physiology, including THC (tetrahydrocannabinol).

The researchers believe that THC may disrupt the way sperm swim, or it may block mechanisms designed to weed out malfunctioning sperm.