1. From the MRC Environmental Epidemiology Unit (C.M.L., A.W.S., C.A.N., H.E.S., C.N.M.), University of Southampton, Southampton General Hospital, Southampton; Royal Brompton Hospital (E.A.S.), London; Department of Public Health (P.M.F.), University of Aberdeen; and Institute of Reproductive and Developmental Biology (M.d.S.), Queen Charlotte’s and Chelsea Hospital, London, United Kingdom.