A study suggests that advanced grandparental age is associated with an increased risk of autism.

The authors of the study looked at the association between paternal age and autism by examining people born in Sweden since 1932.

Using nationwide multi-generation patient registries, they study focused on the association between grandfathers’ age and childhood autism.

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According to the results, men who had fathered a daughter when they were 50 years or older, were 1.79 times more likely to have a grandchild with autism, and men who fathered a son, when 50 years or older, were 1.67 times more likely to have a grandchild with autism. The results are in contrast to men who fathered children when they were 20 to 24 years old.

The study went on to say that older men should not be discouraged to have children. The authors say results may be important to understanding the mechanism behind childhood autism and other psychiatric and neurodevelopmental disorders.

Watch: A mother's story: Living with autism

The study was conndicted by Emma M. Frans, M.Sc., of the Karolinska Institute, and her colleagues.