• Research conducted with general population samples has demonstrated the importance of sex of siblings in the formation of sex-role identification and in the development of sex-role conflict. Information on early family structure was collected from 207 white male alcoholic inpatients. Among those reared in intact families with at least two older siblings, 65 had a second-older sister and only 28 had a second-older brother. This difference cannot be explained by variation in family size, differential sex ratios in birth rates, or greater availability of women in the sibships of the alcoholics. It is consistent with a model that postulates that alcoholism in men may express dependency conflict associated with sex-role identity problems.
Blane HT, Barry H. Sex of Siblings of Male Alcoholics. Arch Gen Psychiatry. 1975;32(11):1403-1405. doi:10.1001/archpsyc.1975.01760290071008