Substantial progress has been made in identifying specific genetic variants contributing to autism, with the pace of these findings accelerating over the past decade. This talk will review evidence that supports the role of genetics in the complex causes of autism. Although more are predicted to be found, over 100 genetic variants have been identified, most of which affect a single gene (e.g. CHD8, SCN2A) and several leading to fewer or more copies of a region on a chromosome (e.g. maternal chromosome 15q11-q13 duplication). Since 3-10% of individuals with autism may currently be diagnosed as having a specific genetic condition associated with their autism, this knowledge may provide important clinical information such as risk for additional medical problems such as epilepsy. In addition, study of these de novo genetic variants is providing information about the complexity of brain development that contributes to autism and is guiding the development of new therapeutics for autism and related comorbidities. Many misconceptions related to the complexity of autism will be addressed. As one example, the most clinically relevant genetic findings are not present in parents and not inherited. Conversely, most cases of autism are due to many, many genetic variations added together to increase risk for autism.