IJ TRANSGENDER - London Congress - Abstract - Is there a Biological Diathesis in Boys with Gender Identity Disorder?

Editors:
Friedemann Pfäfflin,
Ulm University, Germany

Walter O. Bockting,
University of Minnesota, USA

Eli Coleman,
University of Minnesota, USA

Richard Ekins,
University of Ulster at Coleraine, UK

Dave King,
University of Liverpool, UK

Managing Editor:
Noelle N Gray,
University of Minnesota, USA

Editorial Assistant:
Erin Pellett,
University of Minnesota, USA

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ISSN 1434-4599

XVI Harry Benjamin International Gender Dysphoria Association Symposium
17 - 21 August 1999, London

Reflections on "Transsexualism and Sex Reassignment" 1969 -1999

Is there a Biological Diathesis in Boys with Gender Identity Disorder?

Zucker, Kenneth J., Child and Adolescent Gender Identity Clinic, Child Psychiatry Program, Centre for Addiction and Mental Health—Clarke Division, 250 College St., Toronto, Ontario M5T 1R8 Canada (email: zucker@cs.clarke-inst.on.ca)

In this paper, I will take stock of the empirical evidence regarding biological factors in the genesis of gender identity disorder (GID) in children. The paper will begin by considering two models (the sex-dimorphic model and the within-sex variation model) that can guide empirical research on the question of biological influences on GID. It will be noted that these models also guide biological research on sexual orientation development.

The empirical aspect of the talk begins with the clinically obvious observation that children with GID almost never show signs of an obvious somatic intersexuality. Thus, the search for biological factors must focus either on indirect evidence for subtle prenatal hormonal effects that might affect CNS differentiation, but not genital differentiation, or non-hormonal influences (e.g., genes).

I next review several lines of empirical research that are consistent with such subtle biological effects. The review focuses only on boys, since the database is larger for boys than it is for girls because of a marked sex difference in referral rates. Six variables are reviewed: (1) temperament, (2) cognitive ability patterns, (3) sibling sex ratio, (4) birth order, (5) handedness, and (6) birht weight. It is concluded that there is now increasing evidence for a biological diathesis regarding GID in boys, but it is likely that such factors interact in a powerful way with psychosocial and psychodynamic factors within the family matrix and the child’s larger psychosocial world. Directions for future research will also be considered.