Steven Gans, MD is board-certified in psychiatry and is an active supervisor, teacher, and mentor at Massachusetts General Hospital.
Despite the relaxation effects that many people associate with marijuana use, research has shown marijuana has negative effects on the male sexual response.
Obviously, if you are both smoking marijuana, you risk increasing the chances of infertility as a couple.
Furthermore, the effects of marijuana on fertility seem to accumulate over time. This means that although teenage girls who smoke marijuana are more likely to get pregnant, by the time a chronic marijuana smoking woman is in her mid-twenties, she may be more likely to experience a delay in getting pregnant.
Quitting marijuana can be harder than many long-term marijuana users expect, so you and your partner would be wise to quit as soon as possible, while you still have time to get help before getting pregnant. If either or both parents still use marijuana when the baby arrives, you are increasing the risk that your child may use drugs in the future, and parental drug use is implicated in many difficulties for children and families.
Current research suggests that smoking cannabis affects sperm in notable ways. Firstly, it could reduce sperm count and affect morphology.
The authors suggest that the “AEA-binding TRPV1 (transient receptor potential vanilloid type 1) could be involved in the sperm fertilizing ability.” More specifically, they say that “TRPV1 could be involved in the complex mechanisms that make spermatozoa able to fertilize oocytes during the capacitation process in the female genital tract.”
The results showed that the subjects with higher THC levels in their urine had a higher incidence of genetic changes. Although the correlation appears to be clear, we still do not know precisely what these findings mean for men who use cannabis and are thinking about starting a family. Regarding the study results, the senior author, Scott Kollins, Ph.D., a professor in psychiatry and behavioral sciences at Duke, stated:
The Endocannabinoid System, Development, and Fertility
There is also some evidence that there are differences in the endocannabinoid systems found in the sperm of infertile men compared with their fertile peers. The authors of that particular study say that their research “identified unprecedented alterations of the ECS in infertile sperm, that might impact on capacitation and acrosome reaction, and hence fertilization outcomes.”
All the available research suggests that cannabis has an effect on sperm, but what causes these effects? The answer could well lie within the endocannabinoid system.
They also discovered that THC seemed to disrupt a process known as DNA methylation, which is vital for healthy development. This process was altered in thousands of different genes, all of which were involved in two particular cellular pathways. The first pathway was associated with ensuring that organs reach their full size, and the second was linked to growth during development.
The endocannabinoid system is responsible for many of our vital biological functions. It contains receptors known as CB1 receptors, found primarily in the central nervous system and the brain, and CB2 receptors found elsewhere in the body.
And an even earlier study (Kolodny et al, 1974) into testosterone levels in “chronic” cannabis users found that 6 of 17 subjects had oligospermia (low sperm count), and that average testosterone levels in the cannabis-using group were just over half that of the control group. The effect of cannabis on testosterone levels was observed to be dose-dependent.
Although THC and anandamide are both agonists of the CB1-receptors, they greatly differ in structure and therefore have different effects on certain metabolic processes. Anandamide has a much shorter half-life than THC (just a few minutes for anandamide compared to as long as 24 hours for THC). So while anandamide will degrade shortly after it contacts a receptor, THC can remain in nearby adipose tissue for much longer periods, and can continue to stimulate the receptors, ultimately causing overstimulation and potential negative effects.
Sexing Marijuana Plants – How to see if your cannabis plant is male or female
For healthy adult males, it seems that use of THC does indeed cause some negative effects on fertility, which tend to increase with higher doses. However, THC’s endogenous analogue anandamide appears to be critical to the functioning of the male reproductive system.
Clearly, the endocannabinoid system has a role to play in the regulation of processes critical to male reproductive health, such as sperm count, testosterone levels, and levels of other key hormones such as LH.
However, most of these findings are far from conclusive. Either the study included very few participants or confounding factors such as tobacco use aren’t taken into consideration. In fact, more recent research, like this review on infants who were exposed to marijuana in-utero, concludes there aren’t any adverse risks.