Atypical Gender Development – A Review

DES may have the potential to impact on the sex-differentiation of the central nervous system

From an international research group chaired by Dr. Milton Diamond, and organized by the Gender Identity Research and Education Society (GIRES), this exhaustive review of leading research into causes of “atypical” gender identity development included documentation of prenatal DES exposure.


Atypical Gender Development – A Review, Gender Identity Research and Education Society (GIRES), International Journal of Transgenderism, 9 (1): Pages 29-44, Volume 9, 2006 – Issue 1.

Image credit Chainless Photography.

In 2003, the Gender Identity Research and Education Society (GIRES) ran a small symposium in London, assisted by a Trans Group, founded in 1993, with the aim of moving transsexualism from its current categorisation, in the International Classification of Diseases (ICD 10), as a psychiatric disorder. GIRES was awarded additional funding for this project from the King’s Fund-an eminent charity providing funds for medical and scientific work.

The members of the symposium included physicians and specialists in the different areas pertinent to the understanding and the treatment of transsexualism, and also the Member of Parliament who chairs the Parliamentary Forum for Transsexualism. Transsexual people were represented within this group. Members came from the United Kingdom, The Netherlands, Belgium, Japan and the United States of America.

Professor Milton Diamond (USA) chaired the group who collaborated in producing the following paper. The team endeavoured to provide a balanced and comprehensive review of what is currently understood, in the scientific field, regarding atypical gender development and transsexualism.


Evidence of a mechanism that can alter the fetal endocrine milieu is reported by Dessens et al. (1999). They found a raised incidence of transsexualism in children of mothers exposed to anti-epileptic medication during pregnancy. In laboratory conditions, diethylstilbœstrol (DES) has been shown to affect sex differentiation in mice and rats, producing effects such as hypospadias, hypogonadism and cryptorchidism.

Findings that the human fetus is similarly affected by chemicals crossing the placenta are inconclusive, however there is some evidence of this. DES is described as an ‘endocrine disrupter’ (Gorski, 1998, McLachlan 2001; McLachlan et al., 2001), having anti-androgenic and possibly estrogenic effects, which are capable of altering the human fetal environment when administered to a pregnant mother (Toppari and Skakkebaek, 1998; Berkson, 2000). Beyer explains that it crosses the placental and blood-brain barriers, bypassing the feedback system which would normally suppress the body’s production of estrogen (Beyer, 2003; Gorski, 1998).

DES, therefore, may have the potential to impact on the sex-differentiation of the central nervous system. It was widely administered to pregnant women from the 1950s through to the 1980s to prevent miscarriage. A number of defects of sex differentiation occurred in the children born of these pregnancies (Klip et al., 2001) According to self-reports, there appears to be a raised incidence of gender dysphoria experienced by the sons in this group (DES Sons’ International Research Network). It is thus thought that there may possibly be a link between this condition and the prenatal exposure to DES of those sons. This remains a plausible, but unproven hypothesis.

  • Read/download (free access) the full study via gires.

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