Sperm counts are declining alarmingly across the world, according to a seven-year, 53-country study published in the journal Human Reproduction Update.
The authors say the decline in both sperm count and concentration reflects a global crisis related to our modern environment and lifestyle, with broad implications for the survival of the human species.
This study included the first meta-analysis to demonstrate declining sperm counts among men from South and Central America, Asia and Africa.
It also shows that the decline in sperm counts in North America, Europe, and Australia—reported by the same research team in 2017—has continued and even accelerated.
Sperm count and concentration are not only an indicator of human fertility but also of men’s health. Low levels are associated with increased risk of chronic disease, testicular cancer and a shortened lifespan.
“Overall, we’re seeing a significant worldwide decline in sperm counts of over 50 percent in the past 46 years, a decline that has accelerated in recent years,” said lead author Prof. Hagai Levine of Hebrew University of Jerusalem’s Hadassah Braun School of Public Health.
The team included Prof. Shanna Swan at the Icahn School of Medicine, Mount Sinai, New York, and researchers in Denmark, Brazil, Spain, Israel and the United States.
While the study did not examine the causes of sperm count declines, Levine pointed to recent research indicating that disturbances in the development of the reproductive tract during fetal life are linked to lifetime impairment of fertility and other markers of reproductive dysfunction.
Additionally, Levine explained that “lifestyle choices and chemicals in the environment are adversely affecting this fetal development.”
“We have a serious problem on our hands that, if not mitigated, could threaten mankind’s survival,” he said.
“We urgently call for global action to promoted healthier environments for all species and reduce exposures and behaviors that threaten our reproductive health.”
The study was funded by the Grantham Foundation for the Protection of the Environment.