Medical Examiner

The Doomsday Sperm Theory Embraced by the Far Right

The idea that male fertility is on the decline is an old myth dressed up as science.

A bunch of sperm with smiles on their heads swimming
Photo illustration by Slate. Images by Rost-9D/iStock/Getty Images Plus and katrink03/iStock/Getty Images Plus.

The human species is in grave reproductive danger, according to recent headlines. Some scientists say that sperm counts in men around the world have been plummeting, with Western men approaching total infertility by 2045. Far-right “Great Replacement” theorists, who fear that people of color are “replacing” the white population, have taken up the research with gusto.

This all stems from a report published in 2017 in the journal Human Reproduction Update that claims sperm counts among men in North America, Western Europe, Australia, and New Zealand have fallen by some 50 percent since the 1970s. In February of this year, an author on that paper, Shanna Swan, published a book titled Count Down, which elaborates on what the phenomenon means for our future. The lengthy subtitle, How Our Modern World Is Threatening Sperm Counts, Altering Male and Female Reproductive Development, and Imperiling the Future of the Human Race, suggests things could get really bad. But we at the Harvard GenderSci Lab think there simply isn’t enough evidence to warrant doomsday predictions. The reason is that the initial finding of plummeting sperm counts relies on questionable assumptions.

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First, let’s talk about who is actually affected by the supposed problem of declining sperm counts. For their paper, Swan and her colleagues looked at sperm counts recorded in other published studies between 1973 and 2011. They chose to group the relatively limited historical data on population sperm counts into two big categories: “Western” and “Other.” The researchers labeled the United States, Canada, Europe, Australia, and New Zealand—majority-white areas—as “Western.” They lumped all other countries, with their majority brown, Black, and Asian populations, into the category “Other.” Without using the word white, researchers signaled—as anthropologists and psychologists have done when comparing populations around the world—that the men we should be concerned about are white men. With, effectively, white male sperm counts declining, “the future of the human race” is being imperiled. Framed this way, their conclusions have leaked into the world in troubling ways. White nationalists and so-called men’s rights activists are taking up the alarm over the decline of “Western” sperm. In online forums like 4chan and Reddit, men worry that white people are not reproducing at rates that keep up with racialized others, especially immigrants and Black people. As one comment puts it, “humans have doomed themselves” by allowing the “wrong males” to reproduce.

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But this is about more than optics. Separating out majority-white nations in an analysis of historical trends in sperm counts makes it harder to parse what’s actually driving the decline—and to whom that decline is happening. “Western” and “Other” are ineffective scientific categories because they fail to capture the factors most likely to influence sperm count. For example, many hypothesize that pollutants, especially chemicals in everyday plastics, are the most likely culprit behind sperm decline. But “Other” men are just as likely to be exposed to these chemicals as “Western” men: plastics, toxic pollution, and pesticides are as concentrated—sometimes more so—in low- and middle-income countries as they are in wealthy nations. We don’t know what the results would have looked like if scientists had chosen to use “high pollution” vs. “low pollution” regions as categories of analysis instead of “Western” vs. “Other” nations. Maybe, for example, the study would have found declines only among men exposed to certain kinds or levels of pollution.

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And it’s possible that there just isn’t much of an issue at all—even for “Western” males. While sperm counts in “Western” countries may have indeed declined over a few decades, in 2011—the latest data included in the study—they remained well above the infertility threshold. Though it might be intuitive that it’s better for men to be overflowing with sperm, the historically “low” sperm counts likely don’t represent an issue for even the “Western” portion of the human race. In fact, those “low” sperm counts weren’t that different from the counts in “Other” countries back in the 1970s. It’s also not clear that sperm counts are being driven ever lower by some sinister factor. Even if there have been declines in average sperm counts in some men around the globe, it may be a result of normal variation in sperm counts, as we argue in a new paper out in the journal Human Fertility. The sperm decline theory posits that “Western” sperm counts from the 1970s are an optimum from which we have declined and that this decline is something that needs to be fixed.

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But zero evidence supports either of these assumptions. In fact, it would be surprising if there were anything systematically lowering the fertility of men across a large, but specific, swath of the globe. It’s more likely that sperm counts, like other measures of reproductive function such as testosterone and progesterone levels, vary significantly across individuals, time periods, and geographical locations without pathology. To distinguish between cases of normal and pathological variation, and to do justice to the health and fertility of men in all parts of the world, researchers will need to identify local factors, environmental or otherwise, that could plausibly be the cause of long-term trends in human sperm counts, and track them through rigorous study designs created specifically for this purpose. Approaching the question by dividing the world’s men into a racialized “us” vs. “Other,” and then using the resulting data to make broad-brush statements about causes and consequences, is simply unsound science.

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How did these unscientific categories and assumptions make it into the research in the first place? The narrative that white, Western men are in danger of emasculation and disappearance has deep roots in white nationalist discourse. It is tied to a nostalgic cultural myth of a past in which white men held unchallenged power. It is all too easy for scientific institutions, with majority-white researchers, to center white people and further these myths, which circulate often unconsciously. This is why having more diverse voices in scientific research is so important. The recent sperm count decline research demonstrates how racist, sexist, and Eurocentric ideas can get embedded in the categories that scientists use to analyze data. When research is designed, executed, and communicated by people with varied perspectives, problematic assumptions about particular groups are more likely to get caught and addressed. The institutions that fund science, the journals that publish it, and the media outlets that publicize it need to scrutinize findings that make apocalyptic, decontextualized claims about population differences in the ability to reproduce. This is especially crucial when the stories about who is in danger and why feel familiar and convenient. The narrative of Western sperm count decline is, essentially, a myth that we’re all too used to hearing.

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