Leo Lytel was diagnosed with autism as a toddler. But by age 9 he had overcome the disorder. His progress is part of a growing body of research that suggests at least 10 percent of children with autism can "recover" from it — most of them after undergoing years of intensive behavioral therapy. Skeptics question the phenomenon, but University of Connecticut psychology professor Deborah Fein is among those convinced it's real. She presented research this week at an autism conference in Chicago that included 20 children who, according to rigorous analysis, got a correct diagnosis but years later were no...