Children of alcoholics that had been adopted away and had no contact with their biological parents offer the opportunity to answer the 'nature vs nurture' question. Adopted children with an alcoholic biological parent (usually the father) develop alcohol addiction more frequently compared to a control group of adopted children with no alcoholic parent [7,8]. More recent studies have also shown similar results. In these studies the percentage of alcoholism in boys with alcoholic parents (18%) is four times greater than the percentage of a similar group of boys with non-alcoholic parents regardless of whether the children were brought up by the their biological parents or were adopted, and the risk ratio vary between 1.6 and 3.6 in males, and between 0.5 and 6.3 in females [11,12].
