 We will compare the response of these groups to a standardized alcohol challenge using the procedure in place for NIAAA protocols 03-AA-0283 Influence of Age and Gender on Alcohol Metabolism and Acute Responses and 04-AA-0060 The Effect of Ethanol on Cerebral Blood Flow as Measured by Functional Magnetic Resonance Imaging and the Development of Conditioned Response to Ethanol Administration . Participants will be given a standardized IV infusion of an alcohol solution infused to achieve and maintain a target blood alcohol level of 80 mg. Pre and post infusion measures will be made in two areas: 1 subjective response as measured by standardized questionnaires, and 2 measures of physiologic response, to include saccadic eye movements and blood chemistries. We hypothesize that 118GX subjects will have significantly higher subjective response to alcohol challenge than 118AA subjects. We will then repeat the alcohol infusion procedure in all participants twice in the PET scanner, infusing alcohol or saline, and assess displacement of 11C raclopride, a positron emitter labeled ligand which binds preferentially to D2 receptors. We hypothesize that 118GX subjects will have more 11C raclopride displacement after alcohol infusion relative to placebo, indicating greater amounts of dopamine release. 