Professor of Urology and Professor, Oncology Center, at the Johns Hopkins University School of Medicine.  Urologic surgeon and scientist, he is considered the world authority in the science and medicine of male sexual dysfunction. He received his A.B. degree in Biology from Princeton University and M.D. and M.B.A. degrees from Johns Hopkins University.  He performed his post-graduate training in general surgery, urology, and genitourinary reconstructive surgery at the Johns Hopkins Hospital.