Developmental disorder is also one of important themes of child and adolescent psychiatry. Developmental disorders are regarded as a congenital disease, whose cause is associated to some factors. Besides the maternal age, recent studies mention the effects of paternal age on risk of autism spectrum disorder, one of the developmental disorders [3-5]. Since tendency to marry later has advanced in developed countries, the mechanism of onset of developmental disorders is to be studied. On the other hand, the prevalence rate of the autistic spectrum disorders has changed drastically, as from the previous 0.04%; today’s prevalence rate reaches nearly 1% . It is doubtful that the increase of prevalence is explained by better recognition about this disease, and a tendency to marry later. We have to discuss how to set the standard of developmental disorder again, in addition to the investigation of biological etiology.