Yes, according to research, when one child is diagnosed with autism, the next child to come along has about a 20% greater chance of developing ASD than a child with neurotypical older siblings. The chances increase for a third child - when the first two children in a family receive that diagnosis, the chances go up to 32%.
﻿But, it’s important to note that an autism diagnosis might look very different, even among siblings. Genetics can’t necessarily determine the severity of symptoms. In other words: Two siblings with the same autism diagnosis will likely experience the condition differently.