In most of the research on autism it has been noted that the fathers were much older than average(this is when they thought mother's were to blame). In one small study done in Sweden the mothers mean age was 30.7 and the father's mean age was 34. Gillberg 1980. Both of these ages were much older than the mean age of the unaffected population. Here is a recent article on the Reichenberg study. http://www.intelihealth.com/IH/ihtIH/WSIHW000/35320/63153/491833.html?d=dmtHMSContent