With increasing awareness of the importance of genetic influences on autism, there is now a demand from families with an affected member for advice regarding their risk of having an autistic child. Research evidence currently available makes it possible to give families empirical recurrence risks. It is desirable that this information is imparted by those with joint expertise in the diagnosis and treatment of autism and in the genetics of complex modes of inheritance. A protocol for genetic counseling is described, along with the key elements that influence the recurrence risks given to individual couples. There is a need to give information regarding recurrence risks not only for autism but also for the broader phenotype. In addition, couples may have other issues they wish to discuss, which may influence their reproductive decisions.