1. Childrens Hospital of Los Angeles and the University of Southern California School of Medicine, Los Angeles, California
2. Hospital for Sick Children, Toronto, Ontario, Canada
3. Children’s Hospital and Medical Center, Boston, Massachusetts
4. Child Development and Genetics Division, University of Texas Medical School, Galveston, Texas
5. Universitat Teubingen, Reutlingen, Germany
6. John F. Kennedy Institute, Glostrup, Denmark
7. UCLA Medical Center, Los Angeles, California
8. University of California, Department of Psychology, Davis, California
9. National Institute of Child Health and Human Development, Bethesda, Maryland