Extensive New Study Pegs Autism Rate at 1 in 38 The previous estimate was 1 in 100 By Evann Gastaldo, Newser Staff Posted May 9, 2011 6:33 AM CDT 6 comments Comments In this January 2011 still photo taken from video, PBS newsman Robert MacNeil, right, interacts with Nick, his 6-year-old grandson, who inspired his series on autism. (AP Photo/PBS NewsHour) (Newser) – An extensive, five-year study in South Korea suggests as many as 1 in 38 children have traits of autism, a much higher number than was previously thought. The US has estimated in the past that 1 in 100 children have autism characteristics, but that estimate was based only on education and medical records. In contrast, the time-consuming South Korea study looked at children in the general school population as well as those considered high-risk. Two-thirds of the children found to have traits of autism were undiagnosed and were not receiving special services, the AP reports. Researchers do not believe South Korea has more autistic children than the US; rather, they think autism often goes undiagnosed in many nations. "It doesn't mean all of a sudden there are more new children with (autism spectrum disorders)," says one co-author. "They have been there all along, but were not counted in previous prevalence studies." Another expert adds that while some of the previously undiagnosed children could benefit from special services, others might not.