Autism - or autism spectrum disorder (ASD) - is a group of developmental disabilities that most often appears during the first three years of life. It affects how a person communicates and interacts with others. ASDs occur in all racial, ethnic, and socioeconomic groups, but are four times more likely to be found in boys than girls. In 2007, the Centers for Disease Control and Prevention (CDC) found about 1 in 150 eight-year-old children in multiple areas of the United States had an ASD.