Section 1. Introduction

It is a pleasure to open the Proceedings of this Supplement on developments in gonadotrophin treatment and their influence on the oocyte and embryo. Gonadotrophins have been at the heart of assisted human reproduction since the 1950s, and have proved of immense significance to both scientific analyses and clinical practice. They were especially significant for the introduction of IVF and its derivatives and continue to attract intense investigation today. I find distinct comparisons exist between the early days of IVF and those arising today as another revolution in understanding of human endocrinology is promised from the rapid developments in this field.

This meeting provides an example of how this field moved forward in the early twenty-first century. In the following paragraphs, I wish to salute the investigators whose papers are published in this Supplement by stressing two aspects of reproductive endocrinology. The first is a description of work on gonadotrophins, which have influenced my career in initiating IVF since the 1950s. The second theme concentrates on new concepts of oocyte maturation in vitro and in vivo which were essential aspects of IVF since its beginning. Reference will also be made the close timings of ovarian and embryonic development as the oocyte and embryos are formed in response to gonadotrophic stimulation.