Preliminary evidence suggests that there is a reduction in the volume of the brain region planum temporale in both adults and children with autism. The planum temporale (PT) is an auditory processing brain region intimately associated with language processing in the left hemisphere in normal development. Using magnetic resonance imaging (MRI), the researchers will measure the volume of the left hemisphere PT in 20 parents of children with autism, 20 age-matched adults with autism, and 20 adults with no personal or familial history of autism. Language function and family history of language development will also be assessed in the same three groups of adults and correlated to the MRI findings. The researchers hypothesize that reduction in PT volume will be present in the parents of children with autism. Such a finding would bolster the hypothesis that PT volume reduction represents a familial risk factor for language delay in autism.