1. National Center on Birth Defects and Developmental Disabilities, Centers for Disease Control and Prevention, Atlanta, Georgia;
2. Oak Ridge Institute of Science and Education, Oak Ridge, Tennessee;
3. Birth Defects Surveillance Program, Department of Community and Family Health, College of Public Health, University of South Florida, Tampa, Florida; and
4. Florida Birth Defects Registry, Bureau of Epidemiology, Division of Disease Control and Health Protection, Florida Department of Health, Tallahassee, Florida