Uncertainty remains, research sometimes conflicts and biological pathways aren’t always clear. There are competing theories about whether the sperm count decline is real and what might cause it and about why girls appear to be reaching puberty earlier, and it’s sometimes unclear whether an increase in male genital abnormalities reflects actual rising numbers or just better reporting.
Still, the Endocrine Society, the Pediatric Endocrine Society, the President’s Cancer Panel and the World Health Organization have all warned about endocrine disruptors, and Europe and Canada have moved to regulate them. But in the United States, Congress and the Trump administration seemed to listen more to industry lobbyists than to independent scientists.
Patricia Ann Hunt, a reproductive geneticist at Washington State University, has conducted experiments on mice showing that the impact of endocrine disruptors is cumulative, generation after generation. When infant mice were exposed for just a few days to endocrine disrupting chemicals, their testes as adults produced fewer sperm, and this incapacity was transmitted to their offspring. While findings from animal studies can’t necessarily be extended to humans, after three generations of these exposures, one-fifth of the male mice were infertile.
“I find this particularly troubling,” Professor Hunt told me. “From the standpoint of human exposures, you could argue we are hitting the third generation just about now.”
What if anything does all this mean for the future of humanity?
“I do not see humans becoming extinct, but I do see family lines ending for a subset of people who are infertile,” Andrea Gore, a professor of neuroendocrinology at the University of Texas at Austin, told me. “People with impaired sperm or egg quality cannot exercise their right to choose to have a child. That may not devastate our species, but it is certainly devastating to these infertile couples.”
More research is necessary, and government regulation and corporate responsibility are crucial to manage risks, but Swan offers practical suggestions for daily life for those with the resources. Store food in glass containers, not plastic. Above all, don’t microwave foods in plastic or with plastic wrap on top. Avoid pesticides. Buy organic produce if possible. Avoid tobacco or marijuana. Use a cotton or linen shower curtain, not one made of vinyl. Don’t use air fresheners. Prevent dust buildup. Vet consumer products you use with an online guide like that of the Environmental Working Group.
Many issues in headlines today won’t much matter in a decade, let alone in a century. Climate change is one exception, and another may be the risks to our capacity to reproduce.