The World Congress of In Vitro Fertilization and Alternate Assisted Reproduction, held in Jerusalem, Israel, 2-7 April, 1989, was the sixth in the sequence of these Congresses, but was the first to emphasize the major importance and the place of assisted reproductive technologies in the treatment of infertility. The eternal City of Jerusalem witnessed the gathering of more than 1500 participants from allover the world who shared and exchanged knowledge and up-to-date experience in this ever-evolving field. The high quality scientific contributions to the Congress culminated in the publication of this Proceedings. It embraces all-important aspects in the field of in vitro fertilization and alternate assisted reproduction. Papers on controversies and diversities of methods to stimulate the ovaries, imaging techniques, basic research and state-of-the-art papers on ovarian physiology, the role of GnRH and its analog, clinical aspects of IVF treatment and cryopreservation, up-to-date techniques in assisted reproductive technologies that are quickly developing in conjunction with IVF, were included. When should IVF be preferable to surgery? What are the ex pected up-to-date world results and what are the psychological, moral, ethical and religious implications? These are all the concerns of the treating team and are addressed here. Male factor infertility remains a frustrating problem, but advances in the understanding of sperm-egg interaction, sperm evaluation and preparation are reported. Micromanipulation emerges as a possible alternative to bring some relief to this problem, but it also promises to be central in promoting the field of prenatal genetic analysis.