The autism spectrum disorders represent a collective of neurogenetic conditions that have in common altered socialization and communication. Much attention has been given lately to the marked increased in the reported incidence of these conditions. Significant debate also exists as to the basis of the reported increase. Regardless, clinical geneticists and pediatric neurologists alike are seeing a tremendous increase in the number of referrals for autism and related conditions. Continuing advances in genetic testing provide a moving target for the clinician in determining an appropriate diagnostic plan. In this article, we review the most recent advances in genetic testing technology and their potential application to the etiologic evaluation of patients with autism spectrum disorders.