Studies show that cannabis can negatively affect a man sexual health. A study done by the Reproductive Biology Research Foundation and the Missouri Clinical and Biochemical Laboratory found that marijuana does have an impact on testosterone production. Another study done by Harvard Medical School-McLean Hospital found that marijuana did have an effect on testosterone but not a significant one. Keep in mind that these studies were done in cases where marijuana was used for recreational purposes. Individuals using for medical purposes may not experience these same effects. More research needs to be done.