Rapid advances have taken place in various aspects of reproductive biology during the last decade. These advances have centered around several organ systems that comprise the reproductive system and encompass molecular events and structure-function relationships. It becomes important to review these advances in knowledge, at periodic intervals, with respect to feedback systems and regulatory loops that control reproductive processes in vivo. Towards this end, a workshop entitled "Functional Correlates of Hormone Receptors in Reproduction" sponsored by the National Institute of Child Health and Human Development and the Reproductive Biology Study Section of the Division of Research Grants, National Institutes of Health was held in October 1980. The proceedings of the workshop were published by Elsevier Biomedical/New York. This workshop was followed by two workshops sponsored by the Reproductive Biology Study Section of the Division of Research Grants, National Institutes of Health entitled "Role of Peptides and Proteins in Control of Reproduction" in February 1982 and published by Elsevier Biomedical and "Molecular and Cellular Aspects of Reproduction" in October 1985 and published by Plenum Press. It was, therefore, timely to review the current state of knowledge regarding the regulation of ovarian and testicular function by bringing together scientists working in separate and discrete aspects of reproduction to review the functional implications of their research on the regulation of function within the same tissue and also in relationship to feedback systems and regulatory loops with other tissues.