Researchers have studied the importance of genetic influences on risk of alcohol abuse and alcoholism among 3,516 twins from male-male pairs born in
Virginia between 1940 and 1974.
They found that the probability of abusing alcohol was determined by 53% of inherited genes. Thus if parents or grandparents abused alcohol there is a greater than even chance that male offspring will also become alcoholic.
Additionally, the risk is greater among identical twins than non-identical twins. This may be so due to identical twins coming from the same egg and sharing a greater percentage of the same genes patterns. Where as fraternal twins come from different eggs.
Carol A. Prescott, Ph.D. and
Kenneth S. Kendler, M.D. Genetic and Environmental Contributions to Alcohol Abuse and Dependence in a Population-Based Sample of Male Twins. Am J Psychiatry 156:34-40, January 1999.