ABSTRACT
In 1950, Burlington and Lindeman made one of the earliest observations that synthetic chemicals could seriously impair normal reproductive function (see
Proc. Soc. Exp. Biol. Med
., 74, 48-57, 1950). They showed that Leghorn cockerels exposed to DDT had impaired testicular growth and diminished secondary sexual characteristics. A decade or so later, reports began to emerge that women whose mothers had received diethylstilbestrol (DES) during pregnancy experienced difficulties in conceiving and an increased incidence of cervical deformaties and cancer (see also Chapter 8). The first reported case of clear-cell carcinoma in a DES daughter occurred in 1971. More recently, men exposed to DES
in utero
have also been shown to have an increased incidence of reproductive dysfunction. It is now well known but poorly publicized that the source of infertility problems can be traced to the male 50% of the time. About the same time that the DES problem was emerging, Glen Fox, a scientist with the Canadian Wildlife Service, discovered that gulls in Lake Ontario were showing numerous signs of disrupted reproductive function. Females were sitting on eggs that refused to hatch. Males were losing interest in sex, forcing females to pair up to brood over sterile eggs. The eggs themselves frequently were misshapen and fragile. Fox speculated that pollutants such as DDT and PCBs, persistent organic pollutants (POPs) that are now banned, could be responsible. In 1963, Rachel Carson, formerly an aquatic biologist with the U.S. Fish and Wildlife Service, published her book
Silent Spring
, in which she warned that the indiscriminate use of pesticides could have catastrophic environmental effects. By the
mid-1970s, her words were appearing highly prophetic. Since then, numerous classes of chemicals have been shown to possess the ability to modulate or severely disrupt hormonal function, either experimentally or in wildlife.
