Children of older fathers are more likely to have autism, intellectual disability or other mental disorders, new research suggests.

The findings come from a study looking at medical records from more than 2.8 million children born in Denmark between 1955 and 2006.

Researchers looked at how the age of children’s mothers and fathers at the time of birth correlated to occurrences of various mental disorders listed in the World Health Organization’s International Classification of Diseases, including developmental disabilities, schizophrenia, substance abuse, eating disorders and other conditions.

“We found that the overall risk for psychiatric disorders, in particular mental retardation, autism and schizophrenia, increased for those born to a father over the age of 29 years,” said John McGrath of the Queensland Brain Institute in Australia who led the study published this month in JAMA Psychiatry.

“Recent genetic studies have confirmed that the offspring of older fathers have more de novo (or new) mutations. Our new studies suggest that age-related mutations from the father may impact on the mental health of the offspring,” McGrath said.

Children born to fathers age 45 and over had a 34 percent greater risk of developing a mental disorder compared to kids born to dads ages 25 to 29, the study found.

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