A government survey of parents says 1 in 50 U.S. schoolchildren has autism, surpassing another federal estimate for the disorder.
Health officials say the new number doesn't mean autism is occurring more often. But it does suggest that doctors are diagnosing autism more frequently, especially in children with milder problems.
The earlier government estimate of 1 in 88 comes from a study that many consider more rigorous. It looks at medical and school records instead of relying on parents.
For decades, autism meant kids with severe language, intellectual and social impairments and unusual, repetitious behaviors. But the definition has gradually expanded and now includes milder, related conditions.
The new estimate released Wednesday by the Centers for Disease Control and Prevention would mean at least 1 million children have autism.
The number is important — government officials look at how common each illness or disorder is when weighing how to spend limited public health funds.
It's also controversial.