XVII Harry Benjamin International Gender Dysphoria Association Symposium
31 October - 4 November 2001, Galveston, Texas, U.S.A.

Biological Markers of Transsexual Origins

GREEN, RICHARD U.K.
E-mail: richard.green@ic.ac.uk

Four indirect markers of prenatal origins of transsexualism were studied. Hand use preference begins prenatally. It may be sex hormone influenced in utero. Male and female transsexuals were more often non-right handed than non-transsexual controls. Fingerprint patterns begin prenatally and may be sex hormone influenced in utero. Homosexually oriented male and female transsexuals (attracted to partners of the same birth sex) differed from male and female controls. Birth order research of other workers with homosexual males shows an excess of older brothers with a later birth order than with heterosexual males. With our male transsexuals, each older brother increased the odds of that male transsexual being homosexually oriented (attracted to male partners) by 40%. The ratio of maternal aunts to maternal uncles of homosexual males was found by other workers to show a deficit in the expected number of uncles. The mothers of our male transsexuals had fewer brothers than sisters. The loss of males in one generation and the development of feminized sexual identity in the next is explainable by genomic imprinting.