Dr. Aleksandar Rajkovic is a Professor and Marcus Allen Hogge Chair in Reproductive Sciences, Division Chief of Medical Genetics and Medical Director for the Pittsburgh Cytogenomic and Genetic Laboratories in the Department of Obstetrics, Gynecology and Reproductive Sciences, University of Pittsburgh. His research interests lie in the area of gonadal development, with emphasis on germ cell differentiation. The finite pool of primordial follicles is activated continuously with each menstrual cycle to give rise to mature eggs, and the rate of primordial follicle activation determines reproductive life span. Dr. Rajkovic's laboratory has utilized mouse transgenic models to discover novel germ cell–specific transcriptional regulators that play an important role in primordial follicle activation, ovarian failure, and oocyte differentiation. These germ cell–specific transcriptional regulators Nobox, Sohlh1, Sohlh2, and Lhx8 coordinate unique oocyte-specific pathways that determine reproductive life span and ovarian aging. Moreover, his laboratory has discovered a major checkpoint in mammalian meiosis, Hormad1, and has shown that early oocyte loss is independent of meiosis. His current studies focus on mechanisms behind primordial follicle activation, pathways that lead to oocyte differentiation, and the relevance of these pathways to human ovarian failure.