Two recent studies concerning the prevalence of autism in the US have been getting a lot of attention, because they indicate that autism prevalence may be higher than previously estimated. This, of course, fuels the debate over whether or not there are environmental triggers of autism.
One study was conducted by the CDC but has yet to be published. The results were announced ahead of publication by the US Health and Human Services Secretary Kathleen Sebelius to the autism community. She reports that the new prevalence of autism spectrum disorder (ASD) is now estimated at 1% or 100 in 10,000 children. This is an increase over the last few years. In 2002 the prevalence was estimated to be 66 per 10,000.
The second study was published in the journal Pediatrics and is a phone survey of 78,037 parents. They asked if they had any children who had ever been diagnosed with an ASD. Here are the results: