Professor Jeffrey Zajac is Chairman of the Division of Medicine and Director of the Department of Endocrinology at Austin Health; he also holds an Academic Chair at the University of Melbourne. He is a clinical endocrinologist with research interests in clinical and molecular endocrinology. Professor Zajac trained in Medicine at the University of Melbourne and undertook a PhD in the Department of Medicine, Austin and the Repatriation Medical Centre. Following postdoctoral work in the Endocrine Genetics Unit at Massachusetts General Hospital, Boston, he returned to the University of Melbourne, initially at Royal Melbourne Hospital. His clinical research group has had a long term major research program investigating the function of androgens and androgen withdrawal in patients with prostate cancer. These investigations include effects on bone, muscle, cardiovascular risk and metabolic state. He also heads a molecular endocrinology group who use genetically modified mice to investigate two major areas of endocrinology, functions of the androgen receptor and regulation of calcium metabolism. His clinical interests include: 1) general endocrinology; 2) the use, misuse and abuse of testosterone; 3) transgender medicine.