Where does a person go to sign up to participate in these studies?

The surveys indicate that both men and women of all demographics who reported smoking marijuana within the past year also reported that they had more sex.

“Once we found the positive association between marijuana use and sexual frequency, I thought there were be some groups for whom this pattern did not exist,” Einsenberg explained to Huffington Post. “For example, I thought there would be differences based on age, race/ethnicity, education and marital status but for every group examined, we saw the same association.”

Perhaps even more interesting, this positive correlation was not found when the researchers looked at alcohol use. Alcohol use did not correlate to more sex.

Nor did the correlation exist when the researchers looked at other drug use. The senior author explained that this isn’t merely an issue of inhibition. It’s not that people inclined to use drugs or alcohol are just more inclined to have more sex.

Joseph Palamar, from the Department of Population Health at New York University, told CNN that the Stanford researchers presented a “cool epidemiological paper,” but that it did not explain whether people were under the influence of marijuana just before having the extra sex. He said he’d like to see research that showed any direct effect of marijuana on the frequency of sexual intercourse.