Autism spectrum disorder (ASD) describes a set of neurodevelopmental disorders. Despite extensive ASD research lasting more than 60 years, its causes are still unknown. Without indicating the etiology, its development cannot be stopped. Over the years, both the definition and diagnostic criteria have developed. The number of ASD incidence is rising. The economical aspect should also be highlighted. This disorder presents particular challenges to affected children, their parents and physicians. The research of ASD, physician activities, policy making and raising the level of awareness must be coordinated. Special attention should be paid to the problem among adults with ASD.