Noncancer risk assessment: reproductive toxicology.

In summary, the concerns that environmental and other agents are causing adverse effects on reproductive function in humans are real, although the risk is not necessarily well characterized. The range of concerns for the types of effect that agents might have on reproduction span the full range of reproductive events. There is a fairly high background of reproductive disease in humans which decreases the sensitivity for identifying agents that have a subtle, but adverse, effect on reproductive performance of humans. Because our animal studies identify a large number of agents that cause some adverse reproductive effect at the dose levels tested, the concern is raised about the oversensitivity of animal models for predicting adverse effects in humans. Until we better understand the biology underlying the reproductive process of humans and animals, it will be difficult to make animal studies more specific in their predictiveness. Continued research to better understand the biology of reproduction in humans and animals should help to identify the types of data generated in animals that are most predictive of an adverse effect in humans.