A new study has provided the strongest evidence yet that the rate of autism in children rises with the father's age: Advancing paternal age and risk of autism. But questions remain.
The association between old fathers and autism has been known for many years, and the most popular explanation has been genetic: sperm from older men are more likely to have accumulated DNA damage, which might lead to autism.
As I've said before, this might explain some other puzzling things such as the fact that autism is more common in the wealthy; it might even explain any recent increases in the prevalence of autism, if people nowadays are waiting longer to have kids.
But there are other possibilities. It might be that the fathers of autistic people tend to have mild autistic symptoms themselves (which they do), and this makes them likely to delay having children, because they're socially anxious ...
