From Newscientist: "Regular marijuana usage robs men of sexual highs"
"Stoners may be trading sexual highs for the chemical kind. Males who smoke marijuana daily are four times more likely to have trouble reaching orgasm than men who don't inhale, finds a new study of 8,656 Aussies...
And so does the following translate to greater risk of STD's?:
"Even though many male smokers experienced sexual problems, they reported more partners than non-smokers. Marijuana users were twice as likely to have had two or more sex partners in the previous year than men who didn't smoke pot."