Senior Scientist, ANZAC Research Institute, Concord Hospital, Concord, New South Wales, Australia Dr Allan's research team explores the molecular endocrinology of male and female reproductive development and function. Over the past decade, he has established a series of novel transgenic models to dissect the specific actions of gonadotrophins and sex steroids in vivo. One major focus has been to investigate the hormonal control of postnatal-pubertal testicular and germ cell development. Specifically these studies have focused on the somatic Sertoli cell as a master regulator of hormone-induced spermatogenic development. His recent genetic models target the hormonal control and molecular pathways coordinating the functional development of Sertoli cells and the crucial steroidogenic Leydig cell populations.