CNN's Dr. Sanjay Gupta explains the limitations of the CDC's phone survey that found 1 in 50 children has autism, and talks about why a report released by the same government agency last year put that number much lower at 1 in 88.
"I think in part it depends how you count these cases," says Sanjay. "I don't think there's been that significant an increase, but this is more reflective of increased awareness, an increased diagnosis."
The older study used children's medical records as the basis for the data, and in the new study, parents were asked to answer questions over the phone. Sanjay points out the difficulty in comparing the two reports because of the different methodology used, and says in both cases no children were directly observed.
Watch the video to hear Sanjay's full report.
To find out more, read CDC: Number of children with autism higher than previously thought