Large Danish Study Finds No Clear Link Between Cannabis Use and Male Fertility
Among 1,058 young Danish men, ever using cannabis showed no association with semen quality, sperm count, or most reproductive hormones, though a slight FSH increase hinted at possible early testicular effects.
Quick Facts
What This Study Found
In a cohort of 1,058 young men (59% had ever used cannabis), no associations were found between cannabis use and semen volume, concentration, total count, motility, morphology, or DNA fragmentation. The only signal was a non-significant 8% increase in FSH levels among ever-users (95% CI: -2% to 20%).
Key Numbers
1,058 men; 59% ever-used cannabis; no significant associations with any semen parameter; FSH 8% higher in ever-users (95% CI: -2% to 20%, not significant).
How They Did This
Sub-cohort of the Danish National Birth Cohort (Fetal Programming of Semen Quality cohort). 1,058 young men with self-reported cannabis use linked to clinical semen analysis, reproductive hormone measurements, and detailed information on fetal-life exposures.
Why This Research Matters
Previous studies on cannabis and male fertility have produced conflicting results, partly due to poor control for confounders. This study uniquely incorporates fetal-life exposure data, addressing a key limitation of prior research.
The Bigger Picture
The fertility question matters because cannabis is commonly used during reproductive years. This large, well-designed study largely provides reassurance, though the FSH elevation warrants monitoring as it could indicate subtle testicular stress.
What This Study Doesn't Tell Us
Ever-use is a crude exposure measure that does not capture frequency, quantity, or recency. Self-reported cannabis use may underestimate actual exposure. Single semen sample per participant. Young age means long-term effects may not yet be apparent.
Questions This Raises
- ?Does heavy or current cannabis use (vs. ever-use) have different effects on semen quality?
- ?Would the FSH elevation become significant with a more detailed cannabis exposure assessment?
Trust & Context
- Key Stat:
- No significant link to semen quality in 1,058 men
- Evidence Grade:
- Large cohort with clinical outcomes and unique fetal exposure data, but crude cannabis exposure measure limits precision.
- Study Age:
- 2025 publication
- Original Title:
- Ever cannabis use and biomarkers of male fecundity - A study in the Danish National Birth Cohort.
- Published In:
- Reproductive toxicology (Elmsford, N.Y.), 137, 109004 (2025)
- Authors:
- Khoury, Georges, Dan Hull, Sidsel, Ramlau-Hansen, Cecilia Høst, Sørensen, Anne Gaml, Hougaard, Karin Sørig, Petersen, Kajsa Ugelvig, Toft, Gunnar, Deen, Laura, Bonde, Jens Peter, Tøttenborg, Sandra Søgaard
- Database ID:
- RTHC-06820
Evidence Hierarchy
Frequently Asked Questions
Does cannabis affect male fertility?
This large Danish study of 1,058 young men found no significant association between ever using cannabis and semen quality, sperm count, motility, or morphology. A slight increase in FSH was noted but was not statistically significant.
Should men trying to conceive avoid cannabis?
This study found no clear evidence that cannabis history affects semen quality. However, the study measured ever-use rather than current or heavy use, so heavy users may still want to exercise caution during conception attempts.
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Cite This Study
https://rethinkthc.com/research/RTHC-06820APA
Khoury, Georges; Dan Hull, Sidsel; Ramlau-Hansen, Cecilia Høst; Sørensen, Anne Gaml; Hougaard, Karin Sørig; Petersen, Kajsa Ugelvig; Toft, Gunnar; Deen, Laura; Bonde, Jens Peter; Tøttenborg, Sandra Søgaard. (2025). Ever cannabis use and biomarkers of male fecundity - A study in the Danish National Birth Cohort.. Reproductive toxicology (Elmsford, N.Y.), 137, 109004. https://doi.org/10.1016/j.reprotox.2025.109004
MLA
Khoury, Georges, et al. "Ever cannabis use and biomarkers of male fecundity - A study in the Danish National Birth Cohort.." Reproductive toxicology (Elmsford, 2025. https://doi.org/10.1016/j.reprotox.2025.109004
RethinkTHC
RethinkTHC Research Database. "Ever cannabis use and biomarkers of male fecundity - A study..." RTHC-06820. Retrieved from https://rethinkthc.com/research/khoury-2025-ever-cannabis-use-and
Access the Original Study
Study data sourced from PubMed, a service of the U.S. National Library of Medicine, National Institutes of Health.
This study breakdown was produced by the RethinkTHC research team. We analyze and report published research findings without making health recommendations. All interpretations are based solely on the published abstract and study data.