1. Form the Division of Environmental and Occupational Disease Control; CA Department of Public Health; Richmond California 94804
2. Impact Assessment, Inc.; La Jolla California 92037
3. A.J. Drexel Autism Institute; Drexel University; Philadelphia Pennsylvania 19104
4. Gillings School of Global Public Health, The University of North Carolina at Chapel Hill; Chapel Hill North Carolina 27599
5. University of Pennsylvania; Philadelphia Pennsylvania
6. Autism Research Program, Division of Research; Kaiser Permanente; Oakland California 94612
7. The Children's Hospital of Philadelphia, Perelman School of Medicine; Philadelphia Pennsylvania 19104
8. National Center on Birth Defects and Developmental Disabilities; Centers for Disease Control and Prevention; Atlanta Georgia 30341