Declining sperm counts: Nature’s answer to overpopulation?
Epidemiologist Shanna Swan projects that on current trends sperm counts will reach zero by 2045. That shocking conclusion comes from a new book by Swan and her colleague Stacey Colino. Is this nature’s way of bringing human population under control? (More on that later.)
In a 2017 study Swan and colleagues looked at “244 estimates of SC [sperm concentration] and TSC [total sperm count] from 185 studies of 42,935 men who provided semen samples in 1973–2011” in North America, Europe, Australia and New Zealand. Men elsewhere may fare better, but the causes of this trend suggest that it is worldwide.
Swan told The Guardian that she blames so-called “‘everywhere chemicals’, found in plastics, cosmetics and pesticides, that affect endocrines such as phthalates and bisphenol-A.” She also pointed to unhealthy lifestyle choices including use of tobacco and marijuana and to rising obesity. Obesity itself has been linked to increasing human endocrine disruption from these same chemicals.
In fact, Swan’s warning is not new even though her study makes it more urgent. The issue of endocrine disruption from toxic chemicals burst into public view in 1996 with the publication of Our Stolen Future which detailed the research on endocrine disrupting chemicals for a lay audience.
There have been some minor victories. Bisphenol-A has been largely removed from food containers voluntarily by food processors. But it is still found in many products and the U.S. Food and Drug Administration still claims it is “safe.”
I asked at the beginning of this piece whether declining sperm counts is nature’s way of limiting human population. The current trend would not just reduce population, but lead to extinction within a century. It is as if the 2006 film Children of Men has been remade with a slightly different plot line.
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