Study backs theory: parents' age link to autism

The study in the American Journal of Epidemiology finds advanced parental age does indeed appear to boost autism risk in children.

The risk is seen with both mothers and fathers.

The findings may offer clues to understanding the causes of autism and why it's on the rise.

The study found firstborn kids with two older parents were at more than triple the risk of autism, compared to third or later children born to mothers 20 to 34 years old and fathers under 40