The risk of a family with one autistic child having another child with autism is double what was previously thought, according to a new study.
The findings, published in the journal Pediatrics, are of average risks, scientists say: They will vary according to the family's specifics.
"I have seen families with five kids with autism," said Dr. Fred Volkmar, a child psychiatrist and autism expert at Yale University. Volkmar was not part of the study, published Monday.
Scientists have long known that autism runs in families. Still, most previous estimates of the risk of recurrence ranged from 3% to 10%.