'Nightline' Looks at Adult Autism

More than 1 million Americans are autistic. It's the fastest-growing developmental disability, estimated at one in 166 births a year. Much has been reported on autistic youth and as we come to terms with this trend among children, many wonder: What happens when all these children grow up?

As ABC News correspondent John Donvan reports, a significant challenge facing these families is establishing enduring support for their children to last through adulthood and life. Jim and Jen Hoppe -- whose 21-year-old daughter, Jamie, is profoundly autistic -- helped develop a school where Jamie made enormous progress for 16 years.

For the parents of Paul DiSavino, who is 36 and autistic, the concern now is what will happen to their son when they are gone. Their current solution is a group home, but the alternative would be unbearable. Says Paul's mother, Marlene, "He will not survive it ... it would be regressing back to the institutions, back to not caring, just doing, just warehousing them ... not recognizing what's important, and just abandoning them."