New Study Challenges Global Sperm Count Decline Claims

A new study finds no significant decline in sperm counts over six years but notes a drop in motility, possibly due to pandemic lifestyle changes.

New Study Challenges Global Sperm Count Decline Claims
Photo by Deon Black / Unsplash

The belief that men's sperm counts are dropping globally has been called into question by a new study from the University of Manchester, Queen’s University in Kingston, Canada, and Cryos International, Denmark. This study, published in the journal Human Reproduction on June 5, 2024, analyzed data from 6,758 men who applied to be sperm donors at Cryos International, the world’s largest sperm bank.

Study Findings

Contrary to previous meta-analyses suggesting a yearly decline in sperm counts, this new study found no significant change in average sperm concentration over a six-year period from 2017 to 2022. Despite year-to-year variations, the overall sperm concentration remained stable.

Key Points:

  • Sample Size and Period: Data from 6,758 men between 2017 and 2022.
  • Methodology Consistency: Ensured uniformity in measuring sperm concentration and motility.
  • Results: No significant change in sperm concentration over the study period.

Decline in Sperm Motility

Interestingly, the study did find a decline in sperm motility, with the total number of motile sperm decreasing by 16% and 22% from 2019 to 2022.

Possible Factors:

  • COVID-19 Pandemic: The decline coincides with the onset of the pandemic. Researchers speculate that changes in lifestyle during lockdowns, such as altered diets and reduced physical activity, may have impacted sperm motility.

Implications and Future Research

The researchers emphasize that while the study focused on sperm donor applicants in Denmark, it raises important questions about the generalizability of previous findings on global sperm count trends. Monitoring semen quality in donor candidates could provide valuable insights into long-term trends in human semen quality.

This study challenges the widely held belief that sperm counts are universally declining, suggesting that more nuanced and region-specific research is needed. While sperm concentration remains stable, the decline in motility points to the potential influence of lifestyle factors, especially during global events like the pandemic.

Recent decline in sperm motility among donor candidates at a sperm bank in Denmark
AbstractSTUDY QUESTION. Has there been variation in semen quality among men applying to be sperm donors (i.e. donor candidates) in Denmark in recent years