It is the largest international study ever of parental age and autism risk—something we have written about on several occasions. Those previous reports seem to be borne out in these latest findings.
Researchers looked at the national health records of nearly six million children from five different countries—Australia, Denmark, Israel, Norway, and Sweden—including 30,000 with autism. The children of older mothers and fathers have a higher risk of autism.
Previous research often swung back and forth between mothers’ and fathers’ ages as a contributing factor. For the first time this massive study clearly indicates it is both.
It is clear that parental age contributes significantly to the risk of autism. Autism rates were 66 percent higher for children born to fathers over the age of 50) that’s compared to fathers in their 20s. Autism rates were 15 percent higher when mothers had children in their 40s, but also 18 percent higher for teen moms. There was also an increase in autism risk when there was a larger difference between the ages of the mother and father—the rates were higher when fathers were between 35 and 44 and their mates were at least 10 years younger. And the other way around: when mothers were in their 30s and their partners were 10 years younger or more.
--Sarah Hagerty
