New US research has found that those who use marijuana regularly also seem to be having more sex.
Carried out by the Stanford University School of Medicine, the large-scale study looked at 28,176 American women with an average age of 29.9 years and 22,943 American men with an average age of 29.5 taking part in the National Survey of Family Growth.
The survey is carried out on an annual basis and explicitly asks participants how many times they've had intercourse with a member of the opposite sex in the past four weeks and how frequently they've smoked marijuana over the past 12 months.
The researchers compiled the answers to those questions for every year since 2002 to examine for the first time the relationship between marijuana use and frequency of sexual intercourse.
The responses showed that 24.5 percent of men and 14.5 percent of women reported having used marijuana, and that there was a positive association between the frequency of marijuana use and the frequency of sexual intercourse.
The team found that women who reported no marijuana use in the past year had sex on average 6.0 times during the previous four weeks, whereas those who used marijuana daily reported having sex 7.1 times.
For men, those who reported no marijuana use had sex on average 5.6 times during the previous four weeks, whereas for daily users that number increased to 6.9.
This means, according to the study's senior author Michael Eisenberg, MD, that marijuana users are having about 20 percent more sex than abstainers.
The perhaps surprising results go against some previous studies, which have found reduced sperm counts in men who smoke marijuana and reports of erectile dysfunction in heavy users.
However, others have also found in both animals and humans that the drug can stimulate activity in brain regions involved in sexual arousal and activity.
According to Eisenberg, "Frequent marijuana use doesn't seem to impair sexual motivation or performance. If anything, it's associated with increased coital frequency."
Although Eisenberg also noted that the study did not establish a causal connection between the drug and sexual frequency, he added that the result do hint at it.
"The overall trend we saw applied to people of both sexes and all races, ages, education levels, income groups and religions, every health status, whether they were married or single and whether or not they had kids."
In addition, the results still held true even after taking into account the participants' use of other drugs, such as cocaine or alcohol, which Eisenberg believes rules out the explanation that those who are less-inhibited and may be more inclined to use drugs may also be more likely to have sex.
Sexual frequency also increased steadily as marijuana use also increased, suggested that it could play an active role in increasing sexual activity.
Nevertheless, Eisenberg cautioned, "It doesn't say if you smoke more marijuana, you'll have more sex."
The findings can be found published online in the Journal of Sexual Medicine.