He is a well-known clinician, researcher and medical educator best known for his innovative work in the development of egg and embryo donation, fertility care of HIV-seropositive patients, and reproductive bioethics. He currently is a Professor of Obstetrics, Gynecology and Reproductive Sciences at the University of California San Francisco. Dr. Sauer was the Chief of the Division of Reproductive Endocrinology at Columbia University Medical Center in New York City for over twenty-one years, where he was also the program and laboratory director of the Center for Women's Reproductive Care,[1] and a tenured professor and vice-chairman in the Department of Obstetrics and Gynecology at the College of Physicians and Surgeons, Columbia University. While at Columbia University he also served on the Medical Ethics Committee of New York Presbyterian-Columbia University Medical Center.