Uncontrolled population growth, a significant problem for many countries, depresses real living standards in all developing areas. As a corollary, un controlled population growth also stresses the ability to deliver adequate reproductive health care on both national and individual levels. To focus on this and related problems an International Congress to examine many aspects of male and female Reproductive Health Center Care was held on 10-15 October 1982 in Maui, Hawaii, USA. This volume is a result of the proceedings from the 'Symposium on Male Fertility and its Regulation' which was a part of the Reproductive Health Care Congress. The organizers of this symposium recognized the need to focus male reproductive understanding on contraceptive development. The ultimate objective was and still is to produce a variety of safe and effective male contraceptives similar to that accomplished in the female. Speakers were invited to review the state of the art in several areas related to male contra ception, reproductive toxicity and reproductive biology. The abstracts of these sessions were published as a special issue of Archives of Andrology (Vol. 9, No.1, August, 1982). Subsequently, this volume was assembled from key papers presented at the Symposium. Additionally, invited man uscripts from leaders in specific areas were solicited to provide additional range to the topics covered.