According to an article in The Stranger, "Smoking pot is a guy thing. Guys are the ones who deal, buy, and smoke. In 2005, the U.S. Department of Health and Human Services stated that adult males were 50 percent more likely to have smoked marijuana in the last month than females." Could be! Or maybe it's just that women lie more about their stonerosity because it's so much less acceptable for women to look lazy.
Feministing advances this theory in response to the next bit of the article, which talks about how:
Men are allowed to be lazy—being stoned is part of their farting, pajama-wearing, video-game-playing pantheon of acceptable male relaxation techniques ....Their sloth is even kind of adorable. But modern women are not allowed to be lazy, adorable stoners. Women have to go to college (which they're now doing at higher rates than men), and then get their careers going quickly, before their biological clocks run out. Then they have to have kids and take them to all of their activities. There is no time for women to be slovenly and relax—and if women do relax, it has to be at a gym.
Toke Like A Girl