But as for the new research, the CDC was quick to caution that these results may not be applicable to the whole country, as data from only certain sites around the nation was collected. This means that the CDC report relies on the records of many different providers across the country.
Numbers aside, scientists are still searching for what causes autism in the first place.
David Amaral, director of research at the UC Davis M.I.N.D. Institute and past president of the International Society for Autism Research, suggests that this new CDC report "will continue to fuel concerns that environmental factors, which are perhaps largely unidentified, may be increasing the prevalence of autism."
In particular, when asked about vaccines -- which have been a lightning rod for some advocacy groups in past years -- experts are quick to point out that studies have shown no connection to autism.
"As we know from political campaigns, stating a claim repeatedly can lead to a public belief in the concept since these conclusions are not always based on rational thought processes but also on emotional thinking and preconceived notions," says Dr. Max Wiznitzer, associate professor of pediatric neurology at Rainbow Babies and Children's Hospital in Cleveland, Ohio.
"It is clear that more parents are asking questions about vaccines and autism ... with most being reassured when given accurate information and being allowed to be part of the decision making process."
And some doctors said the increase in mild cases being identified may have a silver lining for parents.
"A diagnosis of autism spectrum disorder is no longer the 'kiss of death' it used to be," Rapin said, adding that in some situations, "parents are often eager for the diagnosis because services may be better than for other disorders."