1. Division of Birth Defects and Developmental Disabilities, National Center on Birth Defects and Developmental Disabilities, Centers for Disease Control and Prevention, Atlanta, Georgia;
2. Oak Ridge Institute for Science and Education, Oak Ridge, Tennessee;
3. Computer Sciences Corporation, Atlanta, Georgia; and
4. Division of Neonatal and Developmental Medicine, Department of Pediatrics, School of Medicine, Stanford University, Palo Alto, California