One very thorough study in its attempt to control for other factors that might contribute to mental illness besides CSA [child sexual abuse] surveyed female twins (n=1411), perhaps on the assumption that they would have similar genetic predispositions towards substance abuse and similar developmental environments. These represent a wide range of ages “born between 1934 and 1974.” The family environments in which they were raised were assessed for family disruption and “parental psychopathology,” to distinguish CSA from other causal factors. The survey identified divided CSA into three categories: nongenital (sexual invitation, sexual kissing, and exposing); genital (contact but no intercourse ) and intercourse (with no apparent distinction between oral, vaginal and anal intercourse). The Odds Ratios are for twins where one reported CSA and the other did not, or reported a “less deviant form of CSA,” adjusted for family functioning and parental psychopathology, which might be “genetically transmitted to their offspring.”
The OR for several psychiatric disorders (major depression, generalized anxiety disorder, panic disorder, bulimia nervosa, and substance abuse for both alcohol and other drugs) where more than two disorders were diagnosed were 2.33 (P<.001) for any CSA; 1.42 (not significant) for non-genital CSA; 1.78 (P<.01) for genital CSA; and 4.81 (P<.001) for intercourse.
 Kenneth S. Kendler, Cynthia M. Bulik, and Judy Silberg, et al., “Childhood Sexual Abuse and Adult Psychiatric and Substance Use Disorders in Women: An Epidemiological and Cotwin Control Analysis,” Archives of General Psychiatry 57 [October, 2000], 954.
 Ibid., 955.
 Ibid., 958.
 Ibid., 957, Table 5.