Twin studies (2, 3) have shown that the capacity to master social communication is genetically influenced, and epidemiological studies show that this capacity is distributed in a continuous fashion in the general population, but results from these studies raise further questions about the boundaries separating illness from the extremes of normality. People whose social communication skills fall on the extreme abnormal end of this continuum can readily be diagnosed, using “gold standard” clinical instruments, as meeting the criteria for autism. Our understanding of autism as a spectrum disorder is reinforced because social and communication skills have a continuous distribution. This distribution also suggests how, in future iterations of DSM, we might deal with the severity issue. First, identify suitable diagnostic instruments for the measurement of social communication skills and determine the distribution of social communication scores in the general population using statistics such as the mean and standard deviation. Second, assign cutoff points for severe and moderate autism spectrum disorder that are chosen using clinically appropriate criteria. The diagnostic instruments would vary depending on the age of the child, although the cutoff points should not. It would even be possible to rename moderate autism spectrum disorder as Asperger's disorder, satisfying those who decry the disappearance of this diagnosis from the DSM-5. Lesser degrees of social and communication disorder might not need labeling, although the presence of a mild impairment could be noted. The question of where to place the boundary of social oddity and mild autism could be controversial, and it will require considerable discussion by expert clinicians, parents, and persons with mild autism themselves. We may need a requirement that the symptoms result in a “current impairment in adaptive functioning” (the language used in DSM-IV to define mild mental retardation) to define the diagnosis of mild autism.