Early intervention for autism spectrum disorder (ASD) has proven to be a successful strategy for remediating many difficulties experienced by these children. As a result, accurate diagnoses of children with this range of disorders has become more critical. Additionally, while current training programs are for 3-4 year olds, in efforts to start treatment at younger ages, clinicians are giving these diagnoses at younger and younger ages. A considerable amount of research activity on a technology for making differential diagnoses of ASD has been emerging in recent years. The purpose of this paper is to provide an overview of some of these developments, and to offer opinions on the current status of the area.