Sweden: Children of older men at greater risk of mental illness

Article here. Or perhaps it is equally due to older mothers - or the increased incidence of diagnosing psychiatric illnesses. Excerpt:

'Children born to fathers over the age of 45 are at greater risk of developing psychiatric problems and more likely to struggle at school, according to the findings of a large-scale study.

The research found that children with older fathers were more often diagnosed with disorders such as autism, psychosis, attention deficit hyperactivity disorder (ADHD), schizophrenia and bipolar disorder. They also reported more drug abuse and suicide attempts.

"We were shocked when we saw the comparisons," said Brian D'Onofrio, the first author of the study at Indiana University in the US. But he added that it was impossible to be sure that older age was to blame for the problems.

Researchers at Indiana University and the Karolinska Institute in Stockholm studied medical and educational records of more than 2.6 million babies born to 1.4 million men. The group amounted to nearly 90% of births in Sweden from 1973 and 2001.
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Ryan Edwards, who studies the economics of health and ageing at the City University of New York, said the study revealed "some evidence that paternal age may worsen children's psychiatric, behavioral and educational outcomes."

But he warned that the results hinged on the scientists' comparisons between siblings. "In that setting, it is difficult to separate the overlapping effects of paternal age, children's age, and birth order in a convincing way," he said.

Jennifer Roff, also at the City University of New York, had similar reservations. "I'm not saying that there is no possible genetic role for paternal age. I simply think that this could be confounded with other environmental factors like birth order. The extent of the problem will vary. I can imagine that for things like cognitive scores, this could be a larger problem than for things like schizophrenia."'