Autism risk: Does a father's age play a role?

Is it true that children born to older fathers are at increased risk of autism?

- Kristin / Utah

Mayo Clinic pediatrician Jay Hoecker, M.D., and colleagues answer select questions from readers.

Answer

A growing body of evidence suggests that a father's age (paternal age) may play a role in autism risk.

A large study published in the Archives of General Psychiatry in 2006 examined the relationship between advancing paternal age and autism risk. Researchers reported that children born to men 40 years or older were almost six times more likely to have autism spectrum disorder than were children born to men younger than 30 years.

The reason for this increased risk of autism isn't clear. One theory is that as men age, their genetic material loses some ability to repair itself. As a result, spontaneous mutations in genes may be passed on rather than corrected — potentially leading to an increased risk of brain abnormalities in their children. Researchers have identified a number of gene mutations associated with autism.

On a related note, advancing maternal age appears to have little effect on autism risk.