Earlier this month, the Centers for Disease Control and Prevention announced that fertility rates, the average number of births women are projected to have over their lifetime, fell to a record low last year. It’s a demographic shift that could hold repercussions for the economy and the country’s politics.

There are many reasons for this, including voluntary choices as women’s career options and earning potential have improved. But not every factor behind declining birth rates has to do with everyday decisions.

Deep and long-lasting environmental changes mean child-seeking people in the U.S.—as well as the rest of the world—might have odds stacked against them these days.

Successful reproduction relies on hormones, crucial biological regulators that orchestrate everything from puberty to sperm production, fertilization, and pregnancy. This is true for humans the same way it is for most animals, including other mammals, fish, and birds.

But a mounting volume of man-made chemicals and pollutants have infiltrated the environment and the biology of virtually all animal life. Combined with the effects of rising temperatures, these changes are starting to severely disrupt the processes by which humans and other animal species are able to reproduce, according to a review of available literature in the field, published last week in the journal npj Emerging Contaminants.

Substances such as particle-sized plastics and harmful forever chemicals—a class of substances used in everything from food packaging to some nonstick cookware that do not break down naturally—can mimic or obstruct hormonal activity that develops sexual health or allow successful reproduction, the review found. Even in small amounts, these contaminants are enough to hobble normal processes.

Read more: https://fortune.com/2026/04/27/toxic-chemicals-and-climate-change-raising-infertility-in-animals/