Autism is a baffling brain disorder that profoundly affects children's communication and social skills. It is also a spectrum disorder, which means it can occur in a variety of forms and intensity. Most cases of autism appear before a child's third birthday. Recent years have marked a stunning rise in the number of children diagnosed as autistic, with the U.S. Department of Education reporting a 173-percent rise in the number of autistic students served under the Individuals with Disabilities Act between the 1992-93 and 1997-98 school years. Yet much remains unknown about autism, and...