Falling sperm counts could threaten the human race

Bryan Walsh:

What’s happening: In 2017, Mt. Sinai Medical School epidemiologist Shanna Swan co-authored a sweeping meta-analysis that came to a startling conclusion: Total sperm count in the Western world had fallen 59% between 1973 and 2011. 

  • Together with falling testosterone levels and growing rates of testicular cancer and erectile dysfunction, that translated into a 1% increase per year of adverse reproductive changes for men, according to Swan.

Driving the news: Now Swan has written up her conclusions in a new book with a foreboding title: “Count Down: How Our Modern World Is Threatening Sperm Counts, Altering Male and Female Reproductive Development, and Imperiling the Future of the Human Race.”

  • “If you look at the curve on sperm count and project it forward — which is always risky — it reaches zero in 2045,” says Swan, meaning the median man would have essentially no viable sperm. “That’s a little concerning, to say the least.”

By the numbers: The global fertility rate — the number of births per woman — has fallen from 5.06 in 1964 to 2.4 in 2018.

  • Today, about half the countries in the world — including the U.S. — have fertility rates below the population replacement level of 2.1 births.

  • By 2050, that proportion is projected to rise to two-thirds of nations. 

Yes, but: There are numerous factors connected to falling fertility rates that appear largely unconnected to sperm counts.