Older Parents Are More At Risk Of Having Children With Autism

First Posted: Oct 06, 2016 05:24 AM EDT

The parents' age of conception has a lot to do with the outcome of their children. According to a new study, parents who reproduce later in life are at a higher risk of having children who develop autism disorders.

According to, the study, published in the journal Evolution, Medicine, and Public Health, suggested that late reproduction was not associated with increased risk for schizophrenia in offspring. Researchers from the Copenhagen Centre for Social Evolution have used a very large sample to try to settle the issue, which concluded that late conception leads to a risk of developing schizophrenia in children.

The researchers did a thorough examination of 1.7 million children born in Denmark between 1978 and 2009. The study followed the children until they were 30 years old and found that only 6.5 percent had been diagnosed with autistic or schizophrenic disorders. The information led researchers, including Dr. Sean Byars of the University of Melbourne to compare the children's risks based on maternal and paternal age, and parental age difference.

Researchers found that late reproduction was in no way associated with increased risk for schizophrenia but was with autism. Indian Express reported that the findings also showed that above-average paternal and maternal ages were connected to the increased risk of most autistic disorders in offspring and this effect was more evident in offspring of very old fathers. While discrepancies in parental age added to the risk, at a point where the higher risk for older fathers, it appeared that it could be compensated if the mother was much younger.

It is also important to point out that researchers did not find any connection between advanced maternal and paternal ages and risk of any schizophrenic disorder. Contrary to children of young parents having reduced risks of autism, researchers said that only children of very young mothers had increased risks of schizophrenia, reported NDTV. "The magnitude of these increases and decreases in statistical risk need to be scaled against the fortunately rather modest absolute risks of being diagnosed with a mental disorder," said Dr. Byars.

Meanwhile, authors turned to evolutionary interpretations since they did not find any direct medical explanation to these risks. "Natural selection has shaped how parents, and particularly mothers, allocated their reproductive investments best in the face of uncertain conditions during our prehistory and well into modern historical times," said Professor Jacobus Boomsma, the senior author of the study.

"It was not very long ago that most mothers had their first child around the age of 20 and went through 10 pregnancies. Our modern reproductive patterns are thus a poor match to what humans are likely to be naturally adapted to. Our evolutionary interpretations suggest how we can possibly understand recently increased mental disease risks that have no direct medical explanation."

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