Exposure to hazardous substances and male reproductive health: A research framework

0The discovery in the mid-1970s that occupational exposures to pesticides c ould diminish or destroy the fertility of workers sparked concern about the effects of hazardous substances on male reproductive health. More recently , there is evidence that sperm quantity and quality may have declined world wide, that the incidence of testicular cancer has progressively increased i n many countries, and that other disorders of the male reproductive tract s uch as hypospadias and cryptorchidism mw have also increased. There is grow ing concern that occupational factors and environmental chemical exposures, including in utero and childhood exposures to compounds with estrogenic ac tivity, may be correlated with these observed changes in male reproductive health and fertility. We review the evidence and methodologies that have co ntributed to our current understanding of environmental effects on male rep roductive health and fertility and discuss the methodologic issues which co nfront investigators in this area. One of the greatest challenges confronti ng researchers in this area is assessing and comparing results from existin g studies. We elaborate recommendations for future research. Researchers in the field of male reproductive health should continue working to prioritiz e hazardous substances; elucidate the magnitude of male reproductive health effects, particularly in the areas of testicular cancer, hypospadias, and cryptorchidism; develop biomarkers of exposure to reproductive toxins and o f reproductive health effects for research and clinical use; foster collabo rative interdisciplinary research; and recognize the importance of standard ized laboratory methods and sample archiving.