Does smoking marijuana cause infertility in men?

Generally not but...: If this were a common problem there would be far fewer babies born here in the santa cruz, ca area :) however, there is evidence that heavy marijuana use may lower sperm count somewhat and reduce the ability of sperm to fertilize eggs, but no evidence it causes "infertility" per se. But for couples experiencing fertility issues it would be wise for both partners to reduce or stop marijuana use.