Are Older Parents More Likely to Have Autistic Children?

Question: Are Older Parents More Likely to Have Autistic Children?

Answer: According to recent research, the answer is a qualified "yes." Several studies do seem to suggest that there is an association between parental age and autism. An association, though, is NOT the same thing as a causal connection. That means while older parents may be statistically more likely to have children with autism, no one knows why -- and the reasons may not relate to every couple.

Why would an older parent be more likely to have a child with autism? One possible answer lies in research that shows children with autism are far more likely than typical children to have new (not inherited) genetic mutations. New genetic mutations are often the result of damage to eggs and sperm. Damage to eggs and sperm occurs over time, as parents-to-be are exposed to all kinds of environmental impacts -- everything from cosmic rays to mercury-laden tuna. So the older the parent, the more likely that something will damage eggs or sperm.

But this may not be the reason at all. Another possible explanation is that people with autism -- even very mild autism -- have a tough time socializing and developing intimacy. An adult with autism may take extra time to pair up and have children. As a result, some parents with autistic children may simply have milder forms of autism themselves.

Does this mean that older couples should expect a higher risk of autism? At this point, the jury hasn't completed its verdict -- but the research so far says "yes."

_References: Croen LA, Najjar DV, Fireman B, Grether JK. Maternal and paternal age and risk of autism spectrum disorders. Arch Pediatr Adolesc Med. 2007 Apr;161(4):334-40.

Kolevzon A, Gross R, Reichenberg A. Prenatal and perinatal risk factors for autism: a review and integration of findings. Arch Pediatr Adolesc Med. 2007 Apr;161(4):326-33. Review.

Interview with Dr. J. Sebat, Cold Spring Harbor Laboratory. August, 2007.