By Dr. David Samadi
Recent research conducted by the University of Manchester, Queen’s University in Kingston, Canada, and Cryos International, Denmark, challenges the prevailing notion of a global decline in sperm counts among men. Published in the prestigious journal Human Reproduction on June 5, 2024, this study diverges from prior meta-analyses that have gained widespread attention in mainstream media.
Study methods and results
Examining data from 6,758 men across four cities in Denmark who sought to donate sperm to Cryos International, the world’s largest sperm bank, the study offers a nuanced perspective. While previous meta-analyses suggested a significant decline in sperm counts, the analysis of sperm samples from donor applicants revealed a different picture. Over six years, the average sperm concentration showed variability but did not exhibit a significant downward trend.
Despite Cryos International’s decades-long history, the researchers meticulously focused their analysis on data collected between 2017 and 2022. This deliberate timeframe aimed to ensure consistency in measuring sperm concentration and motility, which are essential factors in assessing sperm quality and fertility potential.
The study challenges the widely held belief in declining sperm counts, as highlighted by Levine et al.’s influential meta-analysis in 2023, which indicated a global decrease in sperm concentrations since 2000.
However, the current study’s findings suggest stability rather than a decline in sperm concentrations among donor applicants in Danish cities between 2017 and 2022.
Questions still unanswered
However, the study does reveal a concerning trend in sperm motility, with both the concentration and total numbers of motile sperm declining by 16% and 22%, respectively, from 2019 to 2022. This unexpected decline, which coincides with the onset of the COVID-19 pandemic, raises significant questions about potential indirect impacts on sperm health. While the study found no direct evidence linking the SARS-CoV-2 virus to sperm quality, the authors suggest that lifestyle changes prompted by pandemic-related lockdowns—such as altered work patterns, dietary habits, and reduced physical activity—may have influenced sperm motility.
Despite limitations in collecting comprehensive health and lifestyle data from donor applicants, the study underscores the importance of monitoring semen quality in this population. Such monitoring not only aids in assessing fertility potential but also contributes valuable insights into broader questions regarding sperm health trends over time.
Moreover, the altruistic act of sperm donation extends beyond individual reproductive assistance, serving as a valuable resource for scientific inquiry. By leveraging data from sperm donor applicants, researchers can shed light on significant questions, including the ongoing debate on global sperm count trends.
While the representativeness of the donor applicant sample vis-à-vis the general Danish population remains uncertain, this study underscores the potential of donor data to advance scientific understanding and address pressing questions in reproductive health.
Dr. David Samadi is the Director of Men’s Health and Urologic Oncology at St. Francis Hospital in Long Island. He’s a renowned and highly successful board certified Urologic Oncologist Expert and Robotic Surgeon in New York City, regarded as one of the leading prostate surgeons in the U.S., with a vast expertise in prostate cancer treatment and Robotic-Assisted Laparoscopic Prostatectomy. Dr. Samadi is a medical contributor to NewsMax TV and is also the author of The Ultimate MANual, Dr. Samadi’s Guide to Men’s Health and Wellness, available online both on Amazon and Barnes & Noble. Visit Dr. Samadi’s websites at robotic oncology and prostate cancer 911.