Christine Stanley will never forget the call. Two weeks after her daughter Emily started kindergarten, the teacher phoned in a panic. Emily would not color, sing or participate in any classroom activities; in fact, she would not say a word to anyone. It was not the first time Christine had received such a call. Emily had not talked at preschool, either. She did not make eye contact with store clerks or talk to nurses at the pediatrician's office. She ran off the playground if another child approached. Mrs. Stanley asked her sister, a special education teacher, what she thought. Mrs....