A group of chemicals
that mimic steroid
hormones in humans
and other animals
. Endocrine disruptors
can affect development
function and sex determination
. Sometimes referred to as "gender bending
The most studied class of endocrine disruptors are estrogen disruptors. Organic estrogen disruptors (called phytoestrogens) are produced by many fungi and plants. Synthetic estrogens include many pesticides (DDT, aldrin, chlordane and dieldrin among others) as well as industrial chemicals (PCBs, dioxins and biphenols). Even though many of these chemicals have been off the market for years, they break down very slowly, and can accumulate in plants and animals.
Evidence of the disruptive effects of synthetic chemicals was first identified in the 1960s, when Rachel Carson singled out DDT as the culprit for the rapidly declining reproduction rates of many popular creatures, most notably bald eagles. Eventually, Rutgers biologist Judith Weis determined that the pesticide was disrupting the eagle's endocrine system, interfering with calcium metabolism and resulting in weak eggshells.
Endocrine disruptors act in 3 primary ways. They can block hormone receptors in cells, cause excessive activation of hormone receptors, or generate an insufficient receptor signal. Harmful effects can occur at concentrations as small as one part per trillion.
All this is above and beyond any other toxic effect these chemicals may have. Hooray for science!