Adam H Balen, MD, MRCOG, Consultant in Obstetrics and Gynaecology and Specialist in Reproductive Medicine, Department of Obstetrics and Gynaecology, Leeds General Infirmary, Leeds, UK; and Howard S Jacobs, MD, FRCP, FRCOG, Professor Reprodcutive Endocrinology, Department of Medicine, UCL Medical School, The Middlesex Hospitals; Consultant to the London Women's Clinic/Hallam Medical Centre Harley Street, London, UK