I was today years old when I learned that “global sperm count” is a thing medical researchers can estimate — and apparently, it has been progressively declining for decades.
An international study published earlier this month in the journal Human Reproduction Update established this trend with a new meta-analysis of “English-language publications that reported primary data on human sperm count.” Data from 38 studies published between 2014 and 2019 were compared with hundreds of studies of semen samples collected from 1973 to 2018. Cisgender men from every continent except Antarctica were represented.
Men who participated in these sperm-count studies were grouped into two categories: unselected, meaning their virility was unknown, and fertile, meaning their partners were already pregnant or had given birth. The meta-analysis indicates that unselected men’s sperm count and mean sperm concentration dropped drastically — we’re talking declines of more than 50 percent — between 1973 and 2018. And those dips have gotten progressively more dramatic since the turn of the century.
Fertile men weren’t exempt, either. Across the board, all men regardless of their fertility status exhibited a decrease in sperm concentration of “0.93 percent each year, and by a total of 41.5 percent between 1973 and 2018.”
“We provide strong evidence, for the first time, of a decline in sperm counts among men from South/Central America, Asia, and Africa, as well as a world-wide decline in the 21st century, with data suggesting that the pace of this decline has accelerated,” researchers wrote.
This study built upon the findings of a 2017 report from the same research team. That analysis only included reports from North America, Europe, and Australia, which led to valid criticism of its narrow geographic scope. (It didn’t help that the 2017 study was unfortunately used as fodder for unfounded speculation about male reproductive health among white supremacist groups.)
Why does the global sperm count appear to be continuously plummeting? Researchers can’t say definitively, although Shanna Swan, an author of the 2022 report, told NBC News it could be linked to the proliferation of endocrine-disrupting pesticides and chemicals in our environment.
“I don’t think there’s any doubt these chemicals affect semen quality,” Swan told the news outlet. “Where there is doubt is how you parse out how much change is due to lifestyle factors and how much is due to chemicals.”
This new report points to a need for further research into men’s reproductive health, the research team wrote. On the positive side, the mean sperm concentration for men in 2018 — 57.1 million swimmers per milliliter of ejaculate, researchers determined — is still higher than levels the World Health Organization considers average.
Per Mayo Clinic, sperm quantity and concentration are important indicators of fertility for people with penises. Having a low sperm count or concentration can make it more difficult to get your partner pregnant because there are fewer sperm available to fertilize an egg.
Before you go, check out the celebrities who shared their abortion stories:
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