Sperm counts have fallen globally at an alarming rate, according to new research by a team based in Israel.
The international team of researchers, led by Professor Hagai Levine of the University of Jerusalem, found that they dropped by more than 62 per cent between 1973 and 2018.
The research covered 53 countries, and analyzed 223 other studies based on sperm samples from over 57,000 men.
It didn’t address the cause of the decline, but many other scientists have identified exposure to certain chemicals and pesticides, smoking, and sedentary lifestyles as key factors.
During the same period, from 1973 to 2018, the concentration of sperm, or the number of sperm per milliliter of a semen sample, among men dropped by more than 51 per cent, from 101.2 million to 49 million.
This number is still above what is considered to be low sperm count – or the total number of sperm in the entire ejaculation – which official health organizations have stated to be below 15 million sperm per milliliter of semen. But research says that fertility begins to drop when concentration dips below 40 million per milliliter.
Low sperm counts are also associated with many health conditions. An Italian study found that men with low sperm counts had higher rates of risk factors that boost the odds of diabetes, heart disease, and stroke.
“Our findings serve as a canary in a coal mine. We have a serious problem on our hands that, if not mitigated, could threaten mankind’s survival,” said Prof Levine.
“We urgently call for global action to promote healthier environments for all species and reduce exposures and behaviors that threaten our reproductive health.”
Prof Shanna Swan, of the New York’s Icahn School of Medicine, and who conducted the research as well, said: “The troubling declines in men’s sperm concentration and total sperm counts at over one percent each year as reported in our paper 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.”
The findings were published in the peer-reviewed journal Human Reproduction Update.