Chemical hazards to human reproduction were evaluated with emphasis on the nature and extent of reproductive toxicity, its causes, and its importance as a public health concern. The human reproductive system and its susceptibility to toxic chemicals were discussed, including prenatal susceptibility to chemical insult, susceptibility of male and female systems, and the relationship between sites of action and observable adverse outcomes. Sources of data on reproductive impairment in human populations were considered, including international surveys of vital statistics, surveillance and research studies, trends and patterns, and the extent of reproductive impairment in the United States. Drugs and other chemicals reported to affect reproductive function in humans were discussed. Experimental assays for the effects of chemicals on reproduction were described, including assays in humans, teratogenicity tests in mammals, three generation reproduction tests in mammals, and the dominant lethal assay in mammals. The concordance between reported effects in humans and measured effects in animals was discussed. Policy issues raised by this report were considered. The authors conclude that the relationship between exposure to chemicals and human reproductive impairment may be an important area of public health concern that deserves further scientific investigation and evaluation.