The Centers for Disease Control and Prevention (CDC) reported findings today from the first and largest summary of prevalence data from multiple U.S. communities participating in an autism spectrum disorder (ASD) surveillance project. The results showed an average of 6.7 children out of 1,000 had an ASD in the six communities assessed in 2000, and an average of 6.6 children out of 1,000 having an ASD in the 14 communities included in the 2002 study.