Abstract
The heritability and prevalence of the gender identity disorder (GID) was examined, as well as its comorbidity with separation anxiety and depression, in a nonretrospective study of child and adolescent twins. The parents of 314 twins (ages 4–17 years; 96 monozygotic pairs [MZ] and 61 dizygotic [DZ] pairs) completed the Coolidge Personality and Neuropsychological Inventory (CPNI) containing a six-item DSM-IV-based GID scale. Prevalence of clinically significant GID symptomatology in the twin sample was estimated to be 2.3%. Univariate model fitting analyses were conducted using an ordinal transformation of the GID scale. The model that best described the data included a significant additive genetic component accounting for 62% of the variance and a nonshared environmental component accounting for the remaining 38% of the variance. Results suggested no heterogeneity in the parameter estimates resulting from age. The correlation between GID and depression was modest, but significant (r = .20; P < .05), whereas the correlation between GID and separation anxiety was nonsignificant (P > .05). Overall, the results support the hypothesis that there is a strong heritable component to GID. The findings may also imply that gender identity may be much less a matter of choice and much more a matter of biology.
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REFERENCES
American Psychiatric Association. (1994). Diagnostic and Statistical Manual of Mental Disorders (4th ed.). Washington, DC, Author.
Bailey, J. M., and Bell, A. P. (1993). Familiality of female and male homosexuality. Behav. Genet. 23:313–322.
Bailey, J. M., Dunne, M. P., and Martin, N. G. (2000). Genetic and environmental influences on sexual orientation and its correlates in an Australian twin sample. J. Personality Social Psychol. 78:524–536.
Bailey, J. M., Pillard, R. C., Neale, M. C., and Agyei, Y. (1993). Heritable factors influence sexual orientation in women. Arch. Gen. Pyschiatry 50:217–223.
Bailey, J. M., Pillard, R. C., Dawood, K., Miller, M. B., Farrer, L. A., Trivedi, S., and Murphy, R. L. (1999). A family history study of male sexual orientation using three independent samples. Behav. Genet. 29:79–86.
Bailey, J. M., and Zucker, K. J. (1995). Childhood sex-typed behavior and sexual orientation: A conceptual analysis and quantitative review. Dev. Psychol. 31:43–55.
Bem, D. J. (1996). Exotic becomes erotic: A developmental theory of sexual orientation. Psychol. Rev. 103:320–335.
Blanchard, R., and Bogaert, A. F. (1996). Homosexuality in men and number of older brothers. Am. J. Psychiatry 153:27–31.
Bradley, S. J., and Zucker, K. J. (1997). Gender identity disorder: A review of the past 10 years. J. Am. Acad. Child Adolesc. Psychiatry 36:872–880.
Bradley, S. J., and Zucker, K. J. (1998). Gender identity disorder [Reply to Menvielle]. J. Am. Acad. Child Adolesc. Psychiatry 37:244–245.
Coates, S., and Person, E. S. (1985). Extreme boyhood femininity: Isolated behavior or pervasive disorder? J. Am. Acad. Child Psychiatry 24:702–709.
Coates, S. W., and Wolfe, S. M. (1995). Gender identity disorder in boys: The interface of constitution and early experience. Psychoanalytic Inq. 15(1):6–38.
Cohen, D. J., Dibble, E., Grawe, J. M., and Pollin, W. (1975). Reliably separating identical from fraternal twins. Arch. Gen. Psychiatry 32:1371–1375.
Coolidge, F. L. (1998). Coolidge Personality and Neuropsychological Inventory for Children: CPNI. Colorado Springs, CO, Author.
Coolidge, F. L., Aksamit, C. R., and Becker, L. A. (1994). Prediction of recidivism in juvenile offenders. Indian J. Psychol. Issues, 2(2):1–6.
Coolidge, F. L., Philbrick, P. B., Wooley, M. J., Bunting, E. K., Hyman, J. N., and Stager, M. A. (1990). The KCATI: Development of an inventory for the assessment of personality disorders in children. J. Personality Clin. Stud. 6:225–232.
Coolidge, F. L., Reilman, B. J., Becker, L. A., Cass, V. J., Coolidge, R. L., and Stocker, R. (1992). Emotional problems and neuropsychological symptoms in juvenile non-violent offenders. J. Personality Clin. Stud. 8(1):7–13.
Coolidge, F. L., Thede, L. L., and Jang, K. E. (2001). Heritability of personality disorders in childhood: A preliminary investigation. J. Personality Disord. 15:33–40.
Coolidge, F. L., Thede, L. L., and Young, S. E. (2000). Heritability and the comorbidity of attention deficit hyperactivity disorder with behavioral disorders and executive function deficits: A preliminary investigation. Dev. Neuropsychol. 17:273–287.
Di Ceglie, D. (2000). Gender identity disorder in young people. Adv. Psychiatric Treatment 6:458–466.
Eaves, L., Rutter, M., Silberg, J. L., Shillady, L., Maes, H., and Pickles, A. (2000). Genetic and environmental causes of covariation in interview assessments of disruptive behavior in child and adolescent twins. Behav. Genet. 30:321–334.
Ellett, J. A. C. (2000). Neuropsychological Dysfunction in Children with Borderline Personality Disorder Features. Unpublished master's thesis, University of Colorado, Colorado Springs, CO.
Friedman, M. C. (1998). The Coolidge Axis II Inventory for Children as a Measure of Attention Deficit/Hyperactivity Disorder and Comorbid Disorders. Unpublished master's thesis, University of Colorado, Colorado Springs, CO.
Gebhard, P. H. (1972). Incidence of overt homosexuality in the United States and western Europe. In Livingood, J. M. (ed.) National Institute of Mental Health Task Force on Homosexuality: Final Report and Background Papers (Publication No. 72-9116, pp. 22 29). Washington, DC: U. S. Dept. of Health, Education, and Welfare.
Green, R. (1987). The “Sissy Boy Syndrome” and the Development of Homosexuality. Yale University Press, New Haven, CT.
Jang, K. L., Livesley, W. J., Vernon, P. A., and Jackson, D. N. (1996). Heritability of personality disorder traits: A twin study. Acta Psychiat. Scand. 94:438–444.
Kirk, K. M., Bailey, J. M., Dunne, M. P., and Martin, N. G. (2000). Measurement models for sexual orientation in a community twin sample. Behav. Genet. 30:345–356.
MacCulloch, M. J., and Waddington, J. L. (1981). Neuroendocrine mechanisms and the aetiology of male and female homosexuality. B. J. Psychiatry 139:341–345.
Menvielle, E. J. (1998). Gender identity disorder [Letter to the editor]. J. Am. Acad. Child Adolesc. Psychiatry 37:243–244.
Neale, M. C., and Cardon, L. R. (1992). Methodology for Genetic Studies of Twins and Families. Kluwer, London.
Neale, M. C., and Maes, H. H. M. (1999). Methodology for Genetic Studies of Twins and Families. Kluwer, Dordrecht, Netherlands.
Sham, P. (1998). Statistics in Human Genetics. Arnold, London.
Snider, M. H. (2000). Sexual Abuse and Borderline Personality Disorder in Children: A Diathesis Stress Model. Unpublished master's thesis, University of Colorado, Colorado Springs, CO.
Whitam, F. L., Diamond, M., and Martin, J. (1993). Homosexual Orientation in Twins: A Report of 61 Pairs and Three Triplet Sets. Paper presented at the meeting of the International Academy of Sex Research, Prague, Czechoslovakia.
Zucker, K. J., and Bradley, S. J. (1995). Gender Identity Disorder and Psychosexual Problems in Children and Adolescents. Guilford Press, New York.
Zucker, K. J., and Green, R. (1992). Psychosexual disorders in children and adolescents. J. Child Psychol. Psychiatry 33:107–151.
Zucker, K. J., Green, R., Coates, S., Zuger, B., Cohen-Kettenis, P. T., Zecca, G. M., Lertora, V., Money, J., Hahn-Burke, S., Bradley, S. J., and Blanchard, R., (1997). Sibling sex ratio of boys with gender identity disorder. J. Child Psychol. Psychiatry 38:543–551.
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Coolidge, F.L., Thede, L.L. & Young, S.E. The Heritability of Gender Identity Disorder in a Child and Adolescent Twin Sample. Behav Genet 32, 251–257 (2002). https://doi.org/10.1023/A:1019724712983
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DOI: https://doi.org/10.1023/A:1019724712983