Studies have found autism and autism traits have increased prevalence among siblings of children diagnosed with autism spectrum disorders. Autism risk for siblings is estimated at 1 in 5 (depending on the source), with twins facing an even higher likelihood if one of them is diagnosed with ASD. Read the article "Siblings Face High Recurrence Risk of Autism" at abcnews.go.com/Health/Autism/siblings-face-high-recurrence-risk-autism/story? id=14290496