Dear Alice,

What are the effects of marijuana on libido and fertility? My boyfriend smokes like crazy, and although he has been smoking for a number of years, I am worried about him.



Dear Endo,

Marijuana has a wide range of physiological, psychological, and behavioral effects that are attributed to the many separate compounds of which it is composed. Historically considered an aphrodisiac, marijuana actually has a complex relationship with sex. In recent surveys on the self-reported effects of marijuana, a third of people report that sex is an important factor in their decision to use marijuana. These respondents stated that marijuana intensified sexual experiences by enhancing libido, control, and touch sensitivity and lowering inhibitions. However, other respondents reported that marijuana made them lose interest in sex, feel too lethargic for sex, or too self-conscious to enjoy it. And still others reported no difference between sex with and without prior marijuana use. Another survey claimed that the majority of users feel horny after smoking, and that 66 percent of subjects reported having marijuana increase the duration of a sexual experience. However, again, other respondents in the survey blamed marijuana for either losing interest in sex or being unable to have an orgasm at least once during sex under the influence. These studies show that marijuana affects people’s libido very differently, so your boyfriend might fall into any of these categories.

With regards to fertility, early studies indicated that long-term marijuana use may result in decreased testosterone levels, decreased sperm counts, and increased sperm abnormalities in male users. However, it now appears that there is little or no effect on testosterone levels of adults, but that sperm production may be reduced. There has been no clear evidence of infertility in males who smoke pot, and the effect on sperm production appears to be temporary and reversible when the smoker abstains. In boys entering puberty, pot may have a more marked hormonal effect. There is some evidence suggesting that cannabis stimulates the body to convert testosterone to estrogen, the female hormone, resulting in delayed puberty for young teens. Whether typical marijuana use causes genetic damage that is passed on to a fetus is not known, but appears doubtful. The subject has been controversial for years, and continues to be debated. However, second hand smoke is another issue to consider, which can be very harmful.

For more information, see Marijuana addiction?, Marijuana or just paranoid?, and Marijuana effects? from the Go Ask Alice! archives and the Related Q&As below. You can also check out NORML, the National Organization for the Reform of Marijuana Laws (who take a liberal perspective).


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