Intended as a tool for use by public health officials, research and regulatory scientists and risk managers, this publication seeks to provide a scientific framework for the use and interpretation of reproductive toxicity data from human and animal studies. It also discusses emerging methodology and testing strategy in reproductive toxicity. The text focuses on approaches to assessing reproductive toxicity in males and females, including sexual dysfunction and infertility, and many aspects of developmental toxicity (following both prenatal and postnatal exposure), from conception to sexual maturation. It is an overview of the major scientific principles underlying hazard identification, testing methods and risk assessment strategies in human reproductive toxicity. It also discusses the evaluation of reproductive toxicity data in the context of the extensive risk assessment methodology that has emerged over the past 10-15 years.