TERATOLOGY 59:181 (1999) Introduction ROBERT L. BRENT The members of the Program Committee would like to thank the Officers and Board of the National Council for Radiation Protection (NCRP) for approving the topic for the 1997 Annual Meeting. The topic we have chosen is one of great interest to scientists and the public who are unfamiliar with the activities of the NCRP. We will be discussing the reproductive risks and effects of all forms of radiation from exposures that occur before conception and from exposures during pregnancy. The first portion of the program will deal with the scientific data pertaining to the preconception and intrauterine reproductive risks of ionizing radiation, microwaves, low frequency electromagnetic fields, and ultrasound. We will be examining the effects of these various forms of radiation on the offspring of parents who were exposed prior to conception and the offspring of mothers who were exposed during pregnancy. Our purpose is to provide you with the reproductive risks following exposures to the various forms of radiation that are related to the physical nature of the radiation and the exposure. Some of these effects are deterministic (threshold) phenomena, and some are stochastic phenomena for r 1999 WILEY-LISS, INC. which there is no hypothetical threshold. Following the scientific presentations, we shall examine the impact of the public’s perception of these risks and the news media’s views of these risks. Besides the usual presentations of epidemiological studies and animal studies, we shall be emphasizing two other parameters that are important in providing a more accurate interpretation of the scientific data. The first concept is the importance of meticulous clinical evaluation of the participants in epidemiological studies. It is not uncommon that excellent clinical evaluations performed on individual patients or as part of epidemiological studies may support or refute the suggestion that the effects observed were caused by a radiation exposure. The second concept deals with the importance of using the basic principles of reproductive biology, teratology, developmental biology, and genetics as part of any evaluation of either animal studies or epidemiological studies. We shall begin by discussing the basic science concepts that pertain to reproductive toxicology, developmental biology, teratology, and genetics.