The herbicide atrazine, used to control weeds, has been found to be the cause of demasculinized frogs even at extraordinarily low levels of exposure. A 2002 report in Proceedings of the National Academy of Sciences discovered that at exposure levels far lower than those normally found in lakes, rivers, streams, and drinking water, frogs had their hormones disrupted by molecules of atrazine. Levels as low as 0.1 parts per billion caused frogs to become hermaphrodites. Under EPA regulations, atrazine levels of three parts per billion are allowed in drinking water.

A study in Nature (2002) produced evidence that amphibians in the wild are being “chemically castrated,” as biologist Tyrone Hayes put it. In areas where atrazine had been applied, 100 percent of male frogs were found with abnormal sex organs. The findings in this study were later replicated by four other research teams.

Low doses of a fungicide called vindozolin, at levels of just a few parts per million, have been found to profoundly alter sexual development in male rats, reducing sperm counts by 90 percent and producing feminization and other deformities. “There is every reason to conclude that the effect translates over into humans,” wrote the four authors of a 1999 study in the journal Toxicology & Industrial Health.

The chemical and pesticide industries have ridiculed these and other related scientific studies. A common attack has been to claim that plants also naturally produce estrogen-mimic chemicals and this could account for reported birth anomalies, though no explanation has been offered as to why plants might have suddenly started trying to poison us.

That industry explanation drew a response from the team of scientists who authored the book Our Stolen Future and who continue to maintain a Web site devoted to endocrine-disrupter chemicals. They point out that synthetic hormone mimics pose an even greater hazard than natural compounds “because they can persist in the body for years, while plant estrogens might be eliminated within a day.”

Fitzgerald, Randall. The Hundred-Year Lie: How to Protect Yourself from the Chemicals That Are Destroying Your Health (p. 154). Plume. Kindle Edition.