Delayed puberty

From the Division of Endocrinology, the Hospital for Sick Children, and the Departments of Pediatrics and Physiology, University of Toronto — both in Toronto (M.R.P.); and the Centre for Endocrinology, William Harvey Research Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London (L.D.). Address reprint requests to Dr. Palmert at the Hospital for Sick Children, 555 University Ave., Toronto, ON M5G 1X8, Canada, or at mark.palmert@sickkids.ca; or to Dr. Dunkel at the Centre for Endocrinology, William Harvey Research Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, Charterhouse Sq., London EC1M 6BQ, United Kingdom, or at l.dunkel@ qmul.ac.uk.