More children in the U.S. may have undiagnosed autism.
An extensive, five-year study found as many as one in 38 kids have traits of autism.
That's much higher than previously thought.
In the past, it was estimated one in 100 American children has autism...
But the estimate was based only on education and medical records.
The new study looked at kids in the general population as well as those considered high-risk.