Humans and wildlife are exposed daily to thousands of chemicals through their nutrition, the air, the water and even through the placenta during foetal development. Although since many years there have been a number of reports associating exposure of wildlife to man-made chemicals and reproductive failure and problems with the development of young, it is only since 1991 that a common thread could link these problems in wildlife. Many of the observed effects were synonymous with what would be expected from disruption of the body’s hormones. Decreased hatching success, reproductive abnormalities, decreased fertility and behavioural abnormalities in fish, turtles, birds and/or mammals were not only recorded in species inhabiting heavily polluted areas such as the Canadian Great Lakes or Lake Apopka in Florida, but were also evident in wildlife in many other regions of the world
Since 1992 several scientists have been suggesting that a number of reproductive disorders in men and female are, as in wildlife, caused by chemicals in the environment. Testicular cancer, urethral abnormalities and the decrease in sperm count and quality in the male and breast cancer and endometriosis in the female are disorders of the reproductive system which have increased in many countries over a short period of time. Therefore they rather seem to reflect changes in environmental factors or "life style" than genetic factors. The present information however, is insufficient to link with certainty these alarming effects to exposure to certain man-made chemicals. This lack of information is caused by the complexity of the endocrine system on the one hand, and by the low levels at which chemical substances can interact with the endocrine system on the other hand.