About 1 in 110 U.S. children have been diagnosed with an autism spectrum disorder, and children who have an older sibling diagnosed with ASD are more likely to receive a diagnosis.
The risk of recurrence among siblings is substantially higher than previously thought by researchers. Although past studies estimated the ASD recurrence risk between 3 percent and 10 percent, a more recent study found the overall risk was 18.7 percent and even higher in families with more than one affected sibling (approximately 32 percent). Male infants experienced nearly three times the risk of female infants at 26 percent versus 9 percent.
