Introduction

By Katy Califf

In the fifties and sixties, some alarming events were catching the eyes of scientists around the world. Bald eagles were suddenly not reproducing at all. Many young birds were dying before hatching, and others were born with severe deformities. Female gulls were nesting with other females. Large die-offs were occurring in many animal populations. For example, almost 18,000 seals died in about 9 months in the Kattegat, the strait between Sweden and Denmark.

Trends were becoming apparent in humans as well. One study estimated that the average human male sperm count had dropped 50% from 1938 to 1990. Incidence of cancer was on the rise.

All of the problems being reported had not been seen before World War II. Over the past few decades, these and countless other happenings have been found to be caused by the hundreds of new synthetic chemicals that have been continuously put into the environment from many sources, such as industry and agriculture. They became known as endocrine disruptors.

While many of these endocrine disruptors are intentional, such as birth control pills, many are from waste and pollution. Others that were not intentional, such as many pesticides, had some alarming unknown side effects. Many of these severe effects don’t appear until decades after exposure and many aren’t readily apparent to the naked eye. Endocrine disruptors cause major deformities in development, altered behavior, lowered tolerance of the immune system, and many other deleterious effects.