Older men are more likely than young ones to father a child who develops autism or schizophrenia, because of random mutations that become more numerous with advancing paternal age, scientists reported on Wednesday, in the first study to quantify the effect as it builds each year. The age of mothers had no bearing on the risk for these disorders, the study found.The study was done by a research group in Iceland and just published in the journal Nature, albeit reported in today's New York Times, and elsewhere. To be sure, the effect is not huge, but it seems clear, nonetheless.
The overall risk to a man in his 40s or older is in the range of 2 percent, at most, and there are other contributing biological factors that are entirely unknown.So, the lesson seems to be that delaying childbearing is not just a decision that a woman needs to contemplate, but men are also an important part of the equation. This is a new kind of gender equality.
But the study...provides support for the argument that the surging rate of autism diagnoses over recent decades is attributable in part to the increasing average age of fathers, which could account for as many as 20 to 30 percent of cases.