I'm sorry your son is retarded and has aspergers. Why don't you ask the experts you are working with regarding Aspergers if they commonly see that a son with aspergers often has a father with aspergers. It is not an inevitablity, but since it is seen in families, that would make it genetic.
Unfortunately, I'm the expert on Asperger's I'm working with. That's unfortunate because I'm not really expert on anyone but my son and there aren't very many people out there who are any more qualified than I am.
I agree with you on the incidence of the father-son connection; I think I see it here in our family and I have seen it in other families, as well. Having said that, I see it as a genetic predisposition rather than a defect; the morbidity (a disorder, per se) comes in when there is a particular type of insult (I believe birth trauma, hypoxia, toxic impact of Pitocin and mercury and probably other things, as well -- remember the Foster sunglass cases where the plant contaminants affected the NEXT generation?)
The Stanford study of families with more than one member concluded that there is a genetic weakness rather than a defect per se. I think they're right about that. The doctor there who (finally) graced us with a certified diagnosis of autism (eight required out of a possible sixteen items, and we met eight) indicated that she thought the Pitocin was showing signs on research of causing an auto-immune reaction by the brain; that is what Dr. Pangsepp's research is supporting, also.