Family, twin, and adoption studies demonstrate the genetic contribution to alcoholism but also confirm an important environmental component. The current rapid developments in genetics are providing candidate genes that can be assessed for a role in alcoholism, and a reported association with the DRD2 receptor gene is still being examined. Alcoholism is a complex behaviour which may be more amenable to genetic studies when dissected into its constituent parts. It is probable that multiple genes contribute to the genetic vulnerability to alcoholism and, hopefully, the effect of some will be of sufficient size so that they can be identified. Identification of these vulnerability factors will allow targeting of preventative efforts but before genetic tests are used clinically the full ethical implications will need to be considered carefully.