New Study Warns Declining Sperm Counts 'Could Threaten Mankind's Survival'

While it may sound like a plot element from a dystopian novel like The Children of Men or The Handmaid's Tale, an alarming study published on Tuesday found that worldwide sperm concentrations and counts have fallen by more than half since the 1970s, an accelerating crisis that experts say could pose an existential threat to humanity if not promptly addressed. 

"The key point that needs to be made is that this is desperately bad news for couple fertility."

Published by an international team of researchers in Human Reproduction Update, the study analyzed data from 57,000 men in 53 countries, with results suggesting that average global sperm concentration declined from an estimated 101.2 million per milliliter in 1973 to 49 m/ml in 2018—a drop of 51.6%—while total sperm counts decreased by 62.3% over the same period.

The paper updates and enhances previous research that was limited in scope to North America, Europe, and Australia. The new paper found that for the first time, men in Africa, Asia, and Latin America are experiencing similar sperm declines as those in the three previously studied regions.

Perhaps most alarmingly, the researchers reported an accelerating rate of decrease, with sperm concentrations dropping by 1.16% each year since 1972—but falling by 2.64% annually since 2000.

Hagai Levine of the Hebrew University of Jerusalem's Hadassah Braun School of Public Health, the lead author of the 2017 and 2022 studies, likened their findings to a "canary in a coal mine."

"We have a serious problem on our hands that, if not mitigated, could threaten mankind's survival," Levine said in a statement. "We urgently call for global action to promote healthier environments for all species and reduce exposures and behaviors that threaten our reproductive health."

What's causing sperm counts to perilously plummet? Levine told Health Policy Watch that "the primary suspect is a mother's exposure to man-made chemicals during pregnancy," with plasticizers, pesticides, herbicides, heavy metals, toxic gases, and air pollution believed to be among the chief culprits.

"We also know exposure in adult life and lifestyle choices such as smoking and poor nutritional habits can be associated with poor sperm count," Levine added.

Study co-author Shanna Swan of the Icahn School of Medicine at Mount Sinai in New York City—and author of Count Down: How Our Modern World Is Threatening Sperm Counts, Altering Male and Female Reproductive Development, and Imperiling the Future of the Human Race—said in a statement that the paper's findings "are consistent with adverse trends in other men's health outcomes, such as testicular cancer, hormonal disruption, and genital birth defects, as well as declines in female reproductive health."

"This clearly cannot continue unchecked," she asserted.

Studies have also shown a steady decline in testosterone levels during the 21st century.

While sperm concentration and count are not the only predictors of fertility, Richard Sharpe, a male reproductive health expert at the University of Edinburgh not involved in the new study, told The Guardian that "the key point that needs to be made is that this is desperately bad news for couple fertility."

"These issues are not just a problem for couples trying to have kids," Sharpe stressed. "They are also a huge problem for society in the next 50-odd years as less and less young people will be around to work and support the increasing bulge of elderly folk."