ENDOCRINE DISRUPTORS AND DEVELOPMENT OF THE REPRODUCTIVE-SYSTEM IN THE FETUS AND CHILDREN - IS THERE CAUSE FOR CONCERN

Reports of decreased semen quality and increased rates of developmenta l abnormalities of the male reproductive trace along with increasing i ncidence of testicular cancer have focused attention on man-made chemi cals as potential causative factors. A biologically plausible hypothes is has been advanced which suggests that man-made chemicals act as end ocrine disruptors through interaction with the estrogen receptor resul ting in altered development of the reproductive tract. Available evide nce suggests that this mechanism may play only a minor role in the pur ported adverse effects described to date.: Man-made chemicals, however , may induce adverse heath effects through mechanisms' independent of the estrogen receptor. Indeed, man-made chemicals have been shown to i nduce adverse effects on thyroid function and androgen-dependent proce sses in animal studies. Hence the focus on estrogenic mimics may be to o simplistic and alternate mechanisms could be more relevant due to ta rget gland exposure levels and potency raf the toxicant. Before it can be concluded that man-made chemicals pose little or no risk to the de velopment of the reproductive I.tract in the fetus and children it wil l be necessary to, at the very least, insure that: 1) exposure scenari os include the most sensitive developmental stage, 2) all endocrine ta rgets have been evaluated for potential effects, and 3) the role of en vironmentally and biologically relevant levels of chemical mixtures in adverse health outcomes have :been evaluated. Due to potential for ex posure, sensitivity of the developing reproductive tract, suggestive e vidence of a possible role of man-made chemicals in developmental abno rmalities of the reproductive tract, and the many outstanding research questions, it is concluded that there is sufficient cause for concern .