New Study Shows Link Between Grandfather's Age and a Child's Chances of Being Diagnosed with Autism

While much research has been done on the relation between a parent's age and the chances of having a child with autism, a new study looks at the effect when removed one generation.

Published March 20 in the Journal of the American Medical Association Psychiatry, the study examined the national records of nearly 6,000 autistic individuals alongside 31,000 non-autistic controls. The records came from Sweden and looked at individuals born as far back as 1932.

The results showed that men who had a daughter when they were 50 or older were 1.79 times more likely to have a grandchild with autism, and in the case of a son the odds were 1.67 times higher when compared to men who had children between the ages of 20 and 24.

Autism can vary dramatically in its effects based on its severity but is characterized by difficulties in social interaction, including verbal and nonverbal communication as well as repetitive behaviors, according to autismspeaks.org.

Other symptoms may include difficulties in motor coordination, attention, sleep and gastrointestinal disturbances.

The Centers for Disease Control (CDC) estimates that 1 in 88 American children fall on the autism spectrum. Breaking that statistic down further, it further estimates that 1 in 54 boys fall on the scale versus 1 in 252 girls.  

This is a ten-fold increase in just 40 years; however, this is believed to be partly due to improvement in diagnosis and awareness.

The study was conducted by King's College London's Institute of Psychiatry, Karolinska Institutet in Sweden and Queensland Brian Institute in Australia.