When a Stafford County jury this month found an autistic teenager guilty of assaulting a law enforcement officer and recommended that he spend 101/2 years in prison, a woman in the second row sobbed.

It wasn't the defendant's mother. She wouldn't cry until she reached her car. It was Teresa Champion.

Champion had sat through the trial for days and couldn't help drawing parallels between the defendant, Reginald "Neli" Latson, 19, and her son James, a 17-year-old with autism.

James might have said this, she thought. James might have done that. She had fresh bruises on her body that showed that James, too, had lost his temper to the point of violence.

"This is what we live with," said Champion, of Springfield. "When they go over the edge, there is no pulling back. "

The cause of autism - a complex developmental disability that affects a person's ability to communicate and interact with others - remains the subject of heated debate. What's not in dispute is the soaring number of children found to have the disorder. In 1985, autism had been diagnosed in one out of 2,500 people in the United States; now the rate is one in 110.

Champion said parents are just beginning to acknowledge what she calls the "dark side of autism," their children's capacity for aggression when they are frustrated, angry or overstimulated. Her son recently hit his attendant and attacked his father in front of a movie theater. Other parents describe scary episodes of biting, kicking and hitting.

It's not easy to talk about children lashing out, Champion said. But it's necessary because many are getting older and bigger and yearn for more independence, which leads to private struggles becoming public.

During Latson's three-day trial, no one disputed that he assaulted a Stafford deputy one morning in May. The deputy was bleeding so profusely that responding officers thought he had been shot.

But why Latson - who has Asperger's syndrome, a relatively mild form of autism - did it and whether he could have stopped himself played a central role in his defense and has engaged the sympathy of parents in the Washington region and beyond.

"Everyone is like, 'Oh my God, that is my son,' " said Ann Gibbons of the advocacy group Autism Speaks. She said the case calls attention to two crucial issues: "How do we protect the community, and how do we protect the impaired individual?"

"And in this case, we didn't protect either," she said.