More than 3.5 million adults and children in the US have autism spectrum disorder (ASD). About one in every 68 babies born will have this syndrome. There have been many children diagnosed with autism spectrum disorder in recent years. With the increasing number of autism spectrum disorders, many people have learned more about this syndrome on their own. However, there are still many misconceptions about autism. Here are 9 things you may not know about autism spectrum disorder, including symptoms, how your child is diagnosed, and available treatments.