Autism spectrum disorder is a pervasive developmental disorder in which, despite thorough research, we still don’t know much about etiology and pathogenesis. Many theories regarding the etiology of ASD have been proposed over the years. The purpose of this assignment is to critically review the quality of articles concerning prenatal rubella virus infections in humans and the risk of developing ASD. If these articles are reliable, they can act as a model for how such prenatal influence, or even immunological disturbances in general, can contribute to the development of ASD. They can also be a basis for new and better research, which hopefully can result in prevention of this developmental disorder. This article also concerns the prevalence of ASD, different theories regarding etiology and some results from recent animal research.There were few articles that dealt with prenatal rubella infection in humans, and they were old (1971-1984). This assignment, limited by the time available, gives no clear answers concerning the association between prenatal infection and ASD. One the other hand, it has made very clear that one has not been able, despite all these years, to discard the hypothesis that prenatal infections can influence vulnerable genes and promote the development of ASD. Further investigation, preferably involving biological material from a diversity of children, including during pregnancy, is essential in the quest for answers, both regarding genes and environmental risk factors.