Men who had children at a middle age of 50 years or older were observed to have an incidence that was almost twice as high of having an autistic grandchild if he fathered a daughter, and almost 1.70 times if he fathered a sun.
This is the first time that a link has been established between the reproductive bahavior of a man and autistic children. Specifically the sexual behavior of the autistic child's grandfather and father.
Autism, however is largely believed to be caused both by environmental factors, in some cases pesticides have been blamed, and genetic predisposition.They can range from a mild form that is coupled with some startling high cognition ability, such as Aspergers, to a severe one in which the child can suffer severe menatl retardation and is almost totally unable to communicate.
Interestingly enough, in the United States the incidence of autism is 1 in 88, whereas in Europe the rate is about 1 in 100.
This new research points to a genetic mutation that is passed on to the child, whose probability becomes higher the older the father is. But it also shows that the grandfather's age is even more important, so that the genetic mutation is in a sense replicated and duplicated in a sense through the generations.
This points to a mutation that might occur in the sperm, since as the sperm cell multiply, the chances of mutation in the human genome becomes higher. In this the mutation may be 'silent', a mutation that does affect the first generation, but manifests itself in the second generation. Some genetic mutations are known to skip a generation.
Autism risk might be cumulative, or also be triggered by environmental factors, or be in concomitance with other risk factors that basically tip the balance and dvelops into the autistic syndrome in a child.
Source: Jama Psychiatry 3.20.13
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