What, exactly, is in our water? That ages-old mystery may have some disturbing answers. A study by CHEM trust has found that the presence of feminizing, or gender-bending, chemicals in the water supply may be altering U.S. wildlife populations.

These chemicals are also referred to as endocrine disrupting chemicals (EDCs) or “hormone disruptors” because of their ability to “de-rail the body’s chemical messenger system.” Effects of exposure include altered hormone levels, reduced sperm count, and genital deformities, among others. In egg-laying species, males are seen to produce Vitellogenin, the protein that precedes the laying of eggs.

The bottom-line effect for most of these species is reduced reproduction and, thus, risk of extinction. Affected species include birds, amphibians, fish, reptiles, otters, deer, bears, antelopes and others. The report also cites “several laboratory studies” that suggest effects of these feminizing chemicals across different generations.

While the extent of water pollution and the various mixtures it produces make it hard to identify exactly which chemicals are the culprits, the report urges that greater caution is taken with all varieties of EDCs that could end up in the water supply. One interesting chemical singled out by the report is bisphenol A, a chemical found in numerous household product and food containers. It also suggests that more time and resources should be dedicated to monitoring wildlife at risk for feminization.

The study does not directly reference the effect of EDCs on humans but does state that since, “All vertebrates have similar sex hormone receptors… observations in one vertebrate wildlife species may serve to highlight pollution issue concerns for other vertebrates, including humans.”