Scientists have found no strong evidence that marijuana use reduces sperm quality in men.
The World Health Organization (WHO) considers a sperm count of 15 million sperm per milliliter of semen or higher as healthy. Counts below this number are seen as low.
A recent peer-reviewed study published in the Journal of Andrology analyzed semen samples from 921 men. Among them, 22.6% were regular cannabis users, and 3.3% used it daily.
The researchers from Boston University School of Public Health reported, “Despite different levels of cannabis use, there was no significant difference in sperm concentration, movement, or shape compared to men who did not use marijuana.”
Some changes in sperm measures were seen but were not statistically significant. This suggests that cannabis use, at least at the levels reported, may not harm male fertility.
In Kenya, cannabis is allowed for medical and scientific use under the Narcotic Drugs and Psychotropic Substances (Control) Act of 2022. However, recreational and commercial use remains illegal.
The study noted that “chronic cannabis use has been linked to lower testosterone and changes in hormones important for semen quality.” Previous research showed mixed results, with some linking heavy marijuana use to poor sperm quality and others finding no clear connection.
The scientists concluded, “Our findings do not settle the debate but add useful information for further research on cannabis and fertility.”
The study also controlled for other factors such as body mass index (BMI), and results remained consistent even among non-tobacco smokers.
Dr. Rajesh Chaudhary, an IVF specialist at Fertility Point, agreed with the findings but pointed out that low sperm quality can result from hormonal imbalances like hypogonadism or genetic conditions such as Klinefelter syndrome.
Klinefelter syndrome is a genetic disorder where men have an extra X chromosome. It can cause undescended testicles at birth, structural issues, or complications from surgeries like hernia repairs.
Other causes of poor sperm quality include testicle overheating, heavy alcohol use, smoking, use of drugs such as marijuana and cocaine, certain medications (like chemotherapy drugs, testosterone therapy, and some antidepressants), and obesity.
Dr. Chaudhary also mentioned that low sperm count can sometimes be hereditary, although these cases are rare.
He advised men to consider genetic testing and microdeletion tests to understand risks for their future children.
Dr. Chaudhary emphasized that sexual performance does not affect sperm quality. A low sperm count can make natural conception harder but does not make it impossible.
Currently, about one-third of infertility cases are due to male factors. In Kenya, sperm quality, including shape, movement, and volume, has been declining.
He added that sperm quality typically declines after age 45 due to DNA damage, but this decline is now being seen in younger men as well.
According to World Bank data, Kenya’s fertility rate dropped from 7.3 children per woman in 1960 to 3.3 children per woman in 2020.
Dr. Joachim Osur, a Nairobi-based sexologist, said scientists need to look beyond sperm when studying cannabis effects.
“We must consider how cannabis affects overall sexual function and social well-being. Recreational use carries risks of addiction and relationship problems. When relationships break down, sexual dysfunctions such as erectile problems often follow,” he said.
Dr. Osur urged researchers to take a broader approach in studying cannabis and male reproductive health.
