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The question: are marijuana laws, sex, and fertility associated?

Sex, drugs, and rock and roll, says the saying from the 1960s. Apart from the rock and roll part, the relationship between marijuana and sex – and fertility – is controversial. For example, researchers found that cannabis compounds had a negative effect on fertility. On the other hand, the relaxing effect of cannabis and the enhanced senses might lead not only to increased sexual activity but also lack of contraception.  As such, behavioral responses might counteract physiological effects.

Research is unequivocal about whether marijuana use leads to an increase in sexual activity, the number of sexual partners, and unprotected sex, or is it that those who are more sexually active seek out marijuana. As such, little is known about a causal relationship between sex and marijuana.

More liberal marijuana policies and cannabis regulation are a natural experiment at population level on the effect of marijuana use. The basis of this natural experiment is that first, medical marijuana is legal in some states and illegal in others.  Second, even within those states where medical marijuana is legal, there is a difference in the timing of permissive medical marijuana laws.

In this background, the question arises: are marijuana laws associated with fertility?

Clinical studies assessing marijuana and fertility

Clinical studies have shown that marijuana leads to hormonal effects in men, which might lead to:

  • Worsened semen quality
  • Impaired sperm motility
  • Ejaculation problems.

In women, marijuana use might disrupt:

  • The menstrual cycle
  • Egg production
  • Embryo implantation.

As such, marijuana use might reduce fertility both in males and in females.

Watch this 2:20 minute video: “Marijuana and fertility”

Behavioral studies assessing marijuana and sex

Behavioral studies have found an association between marijuana use and sexual risk, including:

  • Having sex with more new partners
  • Having more than one sex partner at a time
  • Not using contraception or condoms

Additionally, if medical marijuana reduces pain and improve the quality of the life of pain patients, their sexual activity might also increase.

Medical marijuana laws and marijuana consumption

A growing body of scientific literature supports the notion that – unsurprisingly – medical marijuana laws increase marijuana use. The reasons might be:

  • Increased medical use
  • Diversion of medical to recreational use

Laws, however, might differ in terms of the dates when they become effective as well as whether they allow home cultivation. Furthermore, enforcement of non-medical marijuana use might also change as a spinoff of medical marijuana laws.

The data on marijuana laws and fertility

The researchers used vital statistics data from the National Center for Health Statistics to assess birth counts. They also calculated birth rates, and birth counts in subgroups of women based on ethnicity, marital status, and education.

In addition, behavioral data on marijuana use and sex was available from the National Longitudinal Survey of Youth. As such, the researchers examined a population of youth between 31-30 years of age.

Given that sexually transmitted diseases are a proxy for (high-risk) sexual activity, the researchers obtained male gonorrhea rates from the Centers of Disease Control and Prevention (CDC). Furthermore, they obtained data on condom sales from the Nielsen Retail Scanner database. They used a decrease in condom sales data as a proxy of population-wide increased sexual activity.

The researchers also included a number of other, potentially influencing variables, such as unemployment statistics, poverty estimates, recreational marijuana laws, beer and cigarette taxes, Medicaid coverage, Medicaid eligibility threshold, abortion laws, and same sex marriage laws, just to name a few.

Watch this 3:58 minute video: “Can Smoking Weed Increase Your Sex Drive?”


Medical marijuana laws and marijuana use

The researchers indeed found that medical marijuana laws are linked to an increase in marijuana use in the affected populations. More specifically, medical marijuana laws lead to an increase in marijuana use in the past month. This increase is even larger when looking at home cultivation. As such, the scientists observed an average of two days of use per month, which is an increase of 0.9 days of use per person per month.

Any marijuana use, on the other hand, increased relatively sharply for about two years from a flat pre-period level to another, albeit elevated, flat post-period level. This reflects the legal availability of marijuana in that particular state.

Medical marijuana laws and fertility

Overall, births increased by about 2% when looking at laws in general, and about 3% when looking at home cultivation laws in particular. The scientists confirmed these results with different statistical methods and found a sustained increase in the number of births after the medical marijuana laws were enacted.

They calculated that almost 1 more birth occurred per 1000 women between the ages of 21-30, which is the peak fertility age group.

At the same time, the scientists also calculated that there was a 4.3 percentage points increase in the probability of being sexually active in the past 30 days. Furthermore, they also found a 5% decrease in condom sales after medical marijuana laws were enacted. At the same time, there was a 12% increase in the number of gonorrhea cases among men in those states. However, the gonorrhea rates reverted to the mean after five years.

Marijuana laws and fertility in context

One way to think about these findings is that an increase in births and fertility of 2% due to medical marijuana laws dwarfs in comparison to a 30% reduction in fertility among low income women as a result of opening family planning clinics. On the other hand, this increased fertility is similar to an about 3% decrease in birth rates due to global warming.

When comparing any medical marijuana laws with home cultivation laws, dispensary openings, and non-specific pain provisions, the researchers found that any marijuana laws increased fertility rates regardless of the other types of medical marijuana laws.

They also found that the fertility increase was significantly higher for unmarried people and those without college education. However, since abortions and miscarriages might be different in these groups, and the researchers were unable to assess this information.


Assessing the link between medical marijuana laws and fertility is an exciting combination of medical and social sciences. The findings suggest that the passing of medical marijuana laws lead to increased sexual activity and decreased use of contraceptives among those who are sexually active. As such, medical marijuana laws and fertility have a relationship of cause and effect. Side effects include an increase in sexually transmitted diseases and that some of the pregnancies might be unwanted.


Baggio M, Chong A, Simon D. Sex, marijuana and baby booms. J Health Econ. 2019 Dec 28;70:102283.