This study evaluates multiple aspects of the reaction to two doses of ethanol (0.75 and 1.1 mL/kg) in 30 sons of alcoholic fathers and 30 matched controls with no known alcoholic relatives. Based on results of prior research, the evaluations included the postethanol changes in subjective feelings, levels of body sway or static ataxia, and plasma levels of prolactin and cortisol. A stepwise discriminant function analysis on the sample of 60 men revealed that four items (maximum terrible subjective feelings after high dose, cortisol values at two time points after high dose, and prolactin results after low dose) combined to correctly identify 83% of the controls and 70% of the sons of alcoholics. This included approximately 40% of each group whose discriminant scores were +1 or -1 and who were considered to be solidly classified. These results were relatively robust on a jackknife validation procedure. Results of a search for independent factors in the cluster of test scores after ethanol using a principal components analysis were consistent with the discriminant analysis, indicating the possibility of three overlapping domains of the ethanol response, including subjective feelings after the high-dose ethanol challenge (explaining 46% of the variance), hormonal changes after high-dose ethanol along with body sway items (14% of variance), and prolactin changes after low-dose ethanol (9% of variance). There were few background differences between men who had been properly and improperly classified.