Autism is the fastest growing developmental disability in the U.S. Researchers thought of it as a life-long disorder, but that might not be the case.

Jack’s mom Leslie Griggs knew something was different about her son.

“He wasn’t making a lot of eye contact. He didn’t have any words,” she said.

Jack has autism. Griggs says daily therapy sessions have made all the difference for him.

“He seems like he’s more aware of us being in his world. He’s not in his own little world anymore,” she said.

While Jack has shown big improvements, a new study suggests some kids may actually “outgrow” the disorder. Researchers looked at 34 patients with autism who were diagnosed by age five, but now appear to function normally. The study found they no longer meet the criteria for autism. In fact, in tests looking at socialization and communication, the autism patients performed just as well as typical children.

“Now I can say there’s a chance that your kid might outgrow it,” said Dr. Chaouki Khoury, Director of Our Children’s House at Baylor in Dallas, Texas.

Khoury says he’s encouraged by the new study, even though the research did not examine why the patients seemed to “outgrow” the disorder.

“How do you outgrow biting your nails? You learn not to bite them. So outgrowing a behavioral problem is basically learning a different behavior that takes over,” Khoury explained.

Some believe it’s the intensive therapies that cause the dramatic improvements, others think the kids may be on a different part of the autism spectrum that predisposes them to outgrow the condition without therapy.

Griggs hopes with therapy Jack will “swing” into even bigger improvements and possibly outgrow his autism.

“Every parent, I think, hopes the diagnosis will fall off,” she said.

Researchers are now analyzing data to see if there is a link between certain types of therapy and optimal outcomes. Based on previous studies, some believe between 10 and 20 percent of children who were diagnosed with autism may achieve optimal outcomes.