Children born to parents over the age of 35 have a greater risk of being on the autism spectrum, scientists have said.

However, the researchers, from the University of Aarhus School of Public Health, Denmark, said it made no difference to the results if one parent or both parents were over the age of 35.

The scientists looked at details of more than 9,500 children who had been diagnosed with an autism spectrum disorder. They found that children born to fathers in their late thirties were 28 per cent more likely to be born with autism compared to fathers under 35. This increased to between 37 and 55 per cent for children born to fathers over the age of 40.

Similar results were found in mothers - 21-37 per cent more likely to have a child born on the autism spectrum disorder for mothers over 35, and 28-65 per cent more likely when the mother was aged over 40.

In both cases, the age of the spouse had no bearing on the results.

Professor Erik Thorlund Parner said the results may rule out genetic problems caused by older sperm or eggs, because if it was to blame, you would see higher instances of autism if both parents were older.
"The result was surprising as there was no additive effect of maternal and paternal age," he said.

The scientists now plan to undertake a larger analysis of autism and parental age.

Posted by Robert Mair on 3/2/2012