On the Science of Changing Sex

Out of the Frying Pan…

Posted in Transsexual Theory by Kay Brown on January 14, 2010

… Into the Fire.    Or, how to lose even more friends.

androgynous faceI believe that it has now been convincingly demonstrated that there are two and only two major types of MTF transsexuals, that one type is autogynephilic (AGP) and the other is exclusively androphilic. We’ve mostly been talking about the AGP type.  That’s typical of the dialog in the “community” since most transsexuals are AGP and many of them are extremely uncomfortable with the fact.  But, I would now like to turn my attention to the non-AGP, the feminine androphilic type.

It has been noted by a number of people, but most clearly, if not flatteringly, portrayed by Michael Bailey, that the feminine androphilic type transsexual is possibly an extremely feminine form of the more conventionally understood homosexual man.  This too is not a popular notion, both among AGPs, many of whom would otherwise like to identify as a member of the feminine androphilic type, and even among those who would clearly be understood to be members of this feminine androphilic type.  After all, these are people who clearly identify as women, are socially accepted as women, who often marry, and even occasionally adopt and raise children, as women.  But, we are not talking about social or personal identities.  We are talking about biological etiologies.  And there is evidence to support the hypothesis that feminine androphilic transsexuals have the same, or at least similar, etiologies.

First, there is the noted similarity of the obvious behavioral femininity exhibited by the majority of conventional homosexual men before the age of seven and the obvious behavioral femininity seen in feminine androphilic transsexuals at that same age.  In fact, one would be hard pressed to separate them at that age.  Richard Green, testing the hypothesis that feminine boys grow up to be transsexuals, recruited a cohort of such feminine boys in the late 1960s to follow as they grew up, as a longitudinal study.  Of the fifty feminine boys, only one grew up to be transsexual, most grew up to be conventionally homosexual or bisexual.  Interestingly, one grew up to be a heterosexual transvestite.

Other studies involving retrospective reports of childhood behavior of homosexual men have shown the same pattern, that the majority were notably behaviorally feminine as small children.  Thus, not only do most notably feminine boys grow up to be conventional homosexual men, but most gay men were feminine boys.  Similarly, homosexual women have shown the same pattern with respect to behavioral masculinity in early childhood, a trait shared with gynephilic FtM transsexuals, I might add.

So, as young children the two groups, gay men and feminine androphilic transsexuals, are nearly indistinguishable, but by the time they are in puberty, they begin to look quite different in behavior, and often, even physically.  Thus, it could be argued that they are not the same, nor even similar in etiology, given the difference in development pattern between seven and adolescence.

However, there are many other phenomena that suggest a similar, if not the same, etiology.

One of these shared phenomena is the Fraternal Birth Order effect.  Both conventional homosexual men and feminine androphilic transsexuals, as groups, have more older brothers than random chance.  That is to say, that the likelyhood that a male child will be gay or be feminine androphilic transsexual increases by 30% for each older brother that his or her mother has given birth to.  This is not a family constellation effect, as studies have shown that older step-brothers do not influence the odds of being either gay or feminine androphilic transsexual.

Interestingly there is the maternal uncle to aunt ratio mismatch that is shared by both gay men and feminine androphilic transsexuals.  Both groups have more maternal aunts then uncles compared to straight men, significantly more.

Finally, the chance of having a gay brother, for both gay men and feminine androphilic transsexuals is higher than for straight men.

Thus, there are three distinct similarities in family make-up that both conventionally homosexual men and feminine androphilic transsexuals share.

Another similarity is that both gay men and feminine androphilic transsexuals have female like responses to the introduction and sudden reduction of exogenous estrogens, but gynephilic transsexuals do not!  Thus, we have yet more strong evidence for two types of transsexuals, and evidence that the feminine androphilic transsexual is similar to most homosexual men.

The evidence that conventionally homosexual men are neurologically feminized, more like females than straight men, is growing. The most famous is that a certain part of the brain is notably female like in gay men.  But this is only available postmortem.   Other studies using fMRI have shown that when gay men perform certain cognitive tasks that are known to show sexually dimorphic differences in topical brain activation between men and women, the gay men look more like typical women.

Thus, the preponderance of the evidence suggests that feminine androphilic transsexuals are similar to gay men in that both are neurologically feminized, while the AGP transsexuals are not!

One hypothesis is that gay men show a range of femininity and that feminine androphilic transsexuals are the extreme tail end of a distribution that is mostly centered on only mildly feminized.  Indeed, there the are the ranges of femininity exhibited in the gay male population, from unremarkably masculine to feminine, to those who relish joining the ranks of pre-op feminine androphilic transsexuals for short periods, through being drag queens.  Indeed this would parallel the range of autogynephilic behavior, from occasional cross-dresser, to full-time, to post-op transsexual.

Another hypothesis is that there is a dissimilar etiology, but one that causes femininization in similar ways in a neonate, that in gay men, the cause of the femininization is no longer operating in later childhood, allowing the child to masculinize from endogenous hormones, while for feminine androphilic transsexuals, the cause of the feminization is still operating.  For example, if the conventional gay male is caused by the prenatal environment, but postnatally no further developmental interference occurs, then the brain may be further masculinized by endogenous androgens as puberty and adolescence nears.  While for the feminine androphilic transsexual, the effect is from within, perhaps epigenetic inactivation of genes that code for specific androgen receptors in the brain, and possibly elsewhere.  This would explain the observation that feminine androphilic transsexuals are more feminine physically, smaller in stature and slimmer for their height than average males.

There are many possible studies that could be conducted that could show the similarity and possibly the difference between feminine androphilic transsexuals and homosexual men, and likely at the same time, show the dissimilarity between AGP transsexuals and feminine androphilic transsexuals, but most studies of “transsexuals” have not rigorously, if at all, differentiated between AGP and feminine exclusively androphilic transsexuals.  I for one would like to see such studies, to answer such questions as; Are feminine androphilic transsexuals the same or merely similar to gay men?  I would like to see studies that would answer why, in spite of the similarities, we have such extremely divergent life arcs past mid-childhood.  After all, gay men become more masculine as they reach adolescence, while feminine androphilic transsexuals get more feminine.

Although feminine androphilic transsexuals may not be comfortable with knowing that they may share the same etiology as gay men, gay men may return the favor, themselves being uncomfortable with the knowledge that they are feminized males, in the same category as feminine androphilic transsexuals.

But science is about discovering the nature of reality, not about how we would like things to be.

Further Reading:

Essay on Persisting and Desisting Gender Dysphoria in Gender Atypical Children

Essay on Greater Fraternal Birth Order Effect in androphilic transwomen than in gay men


Bailey, J. M., “The Man Who Would be Queen” 2003

Green R (January 1979). “Childhood cross-gender behavior and subsequent sexual preference”. Am J Psychiatry 136 (1): 106–8. PMID 758811.

Bailey, J. Michael; Zucker, Kenneth J. “Childhood sex-typed behavior and sexual orientation: A conceptual analysis and quantitative review”
Developmental Psychology. Vol 31(1), Jan 1995, 43-55.

Blanchard, R., & Sheridan, P. M. (1992). Sibship size, sibling sex ratio, birth order, and parental age in homosexual and nonhomosexual gender dysphorics. Journal of Nervous and Mental Diseases, 180, 40–47.

Blanchard, Bogaert, “Homosexuality in men and number of older brothers”

Anthony F. Bogaert, “Biological versus nonbiological older brothers and men’s sexual orientation”

Green, R. (2000). Birth order and ratio of brothers to sisters in transsexuals. Psychological Medicine, 30, 789–795.

Blanchard, R., Zucker, K., Cohen-Kettenis, P., Gooren, L., & Bailey, J. (1996). Birth order and sibling sex ratio in two samples of Dutch gender-dysphoric homosexual males. Archives of Sexual Behavior, 25, 495–514.

Poasa, K. H., Blanchard, R., Zucker, K. J. (2004). Birth order in transgendered males from Polynesia: A quantitative study of Samoan fa’afafine. Journal of Sex and Marital Therapy, 30, 13–23.

Blanchard, R., (2017). “Fraternal Birth Order, Family Size, and Male Homosexuality: Meta-Analysis of Studies Spanning 25 Years” Archives of Sexual Behavior, https://link.springer.com/article/10.1007/s10508-017-1007-4

Dorner, G., et al., A neuroendocrine predisposition for homosexuality in men

Dorner, G., Neuroendocrine response to estrogen and brain differentiation in heterosexuals, homosexuals, and transsexuals

LeVay S (August 1991). “A difference in hypothalamic structure between heterosexual and homosexual men”. Science (journal) 253 (5023): 1034–7. doi:10.1126/science.1887219. PMID 1887219.

A. Elias, L. Valenta, “Are all males equal? Anatomic and functional basis for sexual orientation in males”  Medical Hypotheses, Volume 39, Issue 1, Pages 85-87


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