Germaine M. Buck Louis, Ph.D., M.S. , is the Director and Senior Investigator of the Division of Epidemiology, Statistics, and Prevention Research (DESPR) at the Eunice Kennedy Shriver National Institute of Child Health & Human Development (NICHD), National Institutes of Health (NIH) in Rockville, Maryland. Robert W. Platt, Ph.D. , is Associate Professor, Departments of Pediatrics and of Epidemiology, Biostatistics, and Occupational Health, and Investigator at Montreal Children's Hospital Research Institute, McGill University, Montreal, Canada.