On the Science of Changing Sex

Brain Power…

Posted in Brain Sex, Confirming Two Type Taxonomy by Kay Brown on December 28, 2015


…I would while away the hours, confir’in with the flowers…. if I only had a brain…”  — Scarecrow, in the Wizard of Oz musical film.

After years of trying to explain the differences between the two types and the statistical evidence for the two type taxonomy of MTF transwomen, I’m now posting what should be the final clincher; solid biomedical laboratory evidence, “proof” even.

Decades ago, as I was researching our collective history and science (the two often go hand in hand), I came across a reference to studies that showed that gay men had feminized brains while MTF transsexuals did not.  SAY WHAT!?!?

Turns out, the study referenced made the false assumption that all MTF transsexuals are the same and had only included gynephilic older transitioners.  Other studies, being aware of, and accounting for the differences between the two MTF transsexual types found something quite interesting, as for example, from the Dörner (1983) abstract:

“In male rats, androgen deficiency during a critical period of sexual brain differentiation was shown to give rise to a predominantly female-differentiated brain. Such animals displayed “homosexual behaviour”, i.e., they were sexually attracted preferentially to partners of the same sex. In addition, they exhibited a sex-specific evocability of a positive oestrogen feedback effect. A positive oestrogen feedback effect on LH secretion was also induced in homosexual transsexual men, in contrast to hetero- or bisexual transsexual men. Thus in homosexual transsexual men, an intravenous injection of 20 mg Presomen (Premarin) produced a significant decrease of serum LH levels followed by a significant increase above the initial LH values. In hetero- or bisexual transsexual men, by contrast, intravenous oestrogen administration, while producing a significant decrease of serum LH levels, was not followed by an increase above the initial LH values. A positive oestrogen feedback effect on LH secretion was also found in homosexual non-transsexual men, in contrast to heterosexual men. These findings suggest that transsexual as well as non-transsexual homosexual men possess a predominantly female-differentiated brain which may be based, at least in part, on androgen deficiency during sexual differentiation of the central nervous system. Homosexual transsexual men also showed an increased LH and FSH response to LH-RH as compared to hetero- or bisexual transsexual men.”

Note that non-exclusively-androphilic (“heterosexual or bisexual”) transwomen did NOT have the female like positive estrogen feedback effect on LH serum levels.  Of course, according the Blanchard’s work, all “non-homosexual” MTF transsexuals should also be in the same taxon, so we would predict that so-called, asexual transsexuals should also show the lack of this positive feedback, and indeed, this too was found, as discribed in the Dörner’s (1976) earlier paper,

“In transsexual men with homosexual behaviour and intact testicular function, as well as in homosexual men with normal gender identity, following a negative oestrogen feedback effect a delayed positive oestrogen feedback action on LH secretion was evoked. By contrast, in transsexual men with hypo- or asexuality and intact testes or hypergonadotrophic hypo- or agonadism, as well as in heterosexual men with normal gender identity, a negative oestrogen feedback effect was not followed by a positive feedback action on LH release. In transsexual women with homosexual behaviour and oligo- and/or hypomenorrhoea, only a weak or at best moderate positive oestrogen feedback action on LH release was evocable, similarly as in castrated and oestrogen-primed heterosexual men. By contrast, in a transsexual woman with bisexual behaviour and eumenorrhoea, a strong positive oestrogen feedback action on LH secretion was evocable, as well as in heterosexual women with normal gender identity.”

Note that in this paper we see a mirror like difference between FtM “homosexual transsexuals” (gynephilic transmen) who respond more like heterosexual men and bisexual FtM transmen who respond more like heterosexual women.  Thus, this data would lend support for there being a taxonic difference between exclusively gynephilic and non-exclusively gynephilic transmen, mirroring the taxonic difference between the two types of transwomen.


These papers, detailing a specific, repeatable, laboratory based test that can differentiate the two types of transsexuals described by Blanchard, “Homosexual” and “Non-Homosexual”, offers both supporting evidence for the two type taxonomy but potentially also a way of independently sorting the two types in future studies.  This difference is a classic medical biomarker for the two types.  Should anyone one doubt the weight of statistical evidence, we can also point to the biomedical evidence via laboratory tests.

Addendum 9/2/2017:

In exploring science, it is important not to cherry pick or ignore papers which fail to support a given hypothesis.  So, I am adding another paper to the list of reference and discussing a paper that on the surface would seem to be contradict Dörner’s results.  Unfortunately, these papers are behind paywalls and I don’t have copies of them… so I clearly don’t have the details… only the abstracts.  Gooren reported in two papers attempts to replicate the LH response and found mixed results, from the ’86 abstract,

“The neuroendocrine response of LH to estrogen administration may be related to sexual dimorphism of the brain, and therefore, homosexual and especially transsexual individuals may differ from heterosexual individuals in their responses. This study failed to find such differences among groups of female heterosexuals, homosexuals, and transsexuals. Specifically, after single dose estrogen administration, all subjects had an initial decline in serum LH levels, followed by a brisk rise of equal magnitude. Among males, the type of response was less uniform. After an initial fall in serum LH levels, the individual responses varied. In 12 of 23 male homosexuals, 10 of 15 male heterosexuals, and all 6 genetic male transsexuals studied, serum LH levels remained below pretreatment levels. In the remaining 11 male homosexuals and 5 of the heterosexuals, serum LH levels increased to values exceeding those before treatment, resembling the response found in the 3 groups of women. Those homosexual and heterosexual men with a rise in serum LH levels to above pretreatment values also had the greatest fall in testosterone levels after estrogen administration, while these same men had the lowest testosterone response to hCG stimulation. I conclude from these results that 1) the similarity of LH responses to estrogen administration in all groups of women studied does not support a theory of brain androgenization as a factor in the establishment of gender identity of sexual orientation; and 2) individual differences in men in the type of LH response to estrogen administration can be satisfactorily explained by endocrine factors, such as Leydig cell function, and need not be related to gender identity, sexual orientation, or other possible causes.”

And in an early ’84 paper,

“In order to test the hypothesis whether there is variation in hormonal levels or response to hormonal manipulation that could permit a distinction between heterosexuals and transsexuals, we designed the following protocol: Six male-to-female (m-to-f) transsexuals, six heterosexual control females and six female-to-male (f-to-m) transsexuals were given estradiol benzoate (E2B) (4.5 micrograms/kg/12 hr) for five days. In the female population, E2B treatment was initiated on day 5 of the menstrual cycle. In all the subjects blood luteinizing hormone (LH) and follicle stimulating hormone (FSH), estradiol-17 beta (E2) and testosterone (T) levels were measured twice daily. Additionally, LH and FSH responses to LHRH (100 micrograms iv) stimulation prior to and on day 5 of the E2B treatment were evaluated. In the m-to-f transsexuals, T levels decreased sharply and progressively during estrogen treatment, along with a fall in LH and FSH levels. The magnitude of the LH and FSH responses to LHRH stimulation also decreased following estrogen administration. In the heterosexual female controls and in the f-to-m transsexuals, estrogen administration increased LH levels to a minimum of 100% above initial values from day 3 onwards.  There was no convincing evidence for the existence of a positive estrogen feedback on LH secretion in m-to-f transsexuals. These results contradict some of the reported hypotheses concerning hormonal alterations in these individuals.”

However, in both studies, Gooren made no effort to differentiate between exclusively androphilic (homosexual) transsexuals and gynephilic/bisexual MTF transsexuals as Dörner did.  Given the copious evidence from statistical and brain morphology research that differentiates the two types of transwomen, this limits the utility of Gooren’s studies.  The only true dissonance between the studies is that Gooren found only a slight difference between homosexual and heterosexual (non-trans) men: 52% of homosexual and 33% of heterosexual men showing a positive LH feedback, while all 6 of the MTF transwomen failed to show any such positive LH feedback.

Although it would appear that this fails to replicate Dörner, I’m astounded that all six of the transwomen failed to show any LH feedback when at least some of the non-transfolk, both homosexual and heterosexual did so.  Without knowing which type of transsexual these subjects are, we can’t really say that this fails to replicate Dörner.  They could all be gynephilic.  There does seem to be small effect size between gay and straight men, but the sample sizes are all too small.  Further, I would be very curious as to how Dörner and especially Gooren determined the sexual orientation of their subjects and whether they were exclusively heterosexual and homosexual.

Interesting that all of the FTM transmen showed an exaggerated LH feedback, hmmmm…

Given the Gooren data, small sample as it is, perhaps adding to it another study regarding the difference between heterosexual and homosexual men?  We have such a study in Gladue, from the abstract,

“A neuroendocrine component, the positive estrogen feedback effect, thought to be related to sexual orientation and, indirectly, to sexual differentiation, was evaluated in healthy, noninstitutionalized research volunteers. Men and women with a lifelong heterosexual orientation and men with a lifelong homosexual orientation were administered an estrogen preparation known to enhance the concentration of luteinizing hormone in women but not in men. The secretory pattern of luteinizing hormone in the homosexuals in response to estrogen was intermediate between that of the heterosexual men and that of the women. Furthermore, testosterone was depressed for a significantly longer period in the homosexual men than in the heterosexual men. These findings suggest that biological markers for sexual orientation may exist.”

Although, to be fair, this study was also small, but when we add them all together, the direction of the effect seems to be real.


Dörner G, Rohde W, Schott G, Schnabl C., “On the LH response to oestrogen and LH-RH in transsexual men.” Experimental Clinical Endrocrinology (1983)

Dörner G., “Neuroendocrine response to estrogen and brain differentiation in heterosexuals, homosexuals, and transsexuals.” Archives of Sexual Behavior (1988)

Dörner G, Rohde W, Seidel K, Haas W, Schott GS.”On the evocability of a positive oestrogen feedback action on LH secretion in transsexual men and women.” Endokrinology (1976)

Gooren L. et al., “Estrogen positive feedback on LH secretion in transsexuality.” Psychoneuroendocrinology (1984)

Gooren L., “The neuroendocrine response of luteinizing hormone to estrogen administration in heterosexual, homosexual, and transsexual subjects.” Journal of Clinical Endocrinology and Metabolism (1986)

Gladue A., Green R. Hellman R., “Neuroendocrine response to estrogen and sexual orientation” Science (1984)



Fun Reading:

All the Stars are Suns ebook completeSincerity Espinoza didn’t go looking for trouble, it found her. All she wants out of life is the chance to go to the stars but she is caught in a web of misunderstandings, political & legal maneuvering, and the growing threat of terrorist plots by religious fanatics. She has a secret that if found out too soon could mean not only her own death but the ruin of the hope for humanity ever going to the stars. But even amidst momentous events, life is still about the small moments of love, laughter, and sadness.   Available as an ebook at Amazon and Kindle Unlimited.


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A Passing Moment…

Posted in Female-to-Male, Science Criticism, Transsexual Field Studies by Kay Brown on December 13, 2015

critical-thinking… Or, Who’s the Fairest of them All?

For years, clinicians, therapists, researchers, and transfolk alike have remarked that “younger transitioners”, transkids, “homosexual transsexuals”, “early onset” (whatever label or demarcator in fashion) MTF transsexuals simply ‘pass’ better than “older transitioners”, autogynephilic transsexuals, “late onset” MTF transsexuals.  For years, I wanted to conduct a study about this.  Well, now we have clinical data to test this observation.

In a study conducted in Europe, by our favorite Netherlands based researchers, they looked at both body image and clinician assessment of gender incongruent physicality.  That is to say, how well or poorly they pass.  The same single clinician rated them all, so while a different clinician may give folks a different absolute score, the relative scores for all subjects is likely to be very accurate.

In deference to the currently debated question and researching the potential validity of which signifier is the accurate basis for a taxonomic typology of transsexuality, the data was presented for both sexual orientation and age of onset.

MtF                                                                 FtM
Androphilic      Non-androphilic           Gynephilic Non-gynephilic
Early onset 88 (70%) 102 (43%)                   193 (88%)   37 (69%)
Late onset  38 (30%)   139 (57%)                   26 (12%)     17 (31%)

The Dutch have long contended that age of onset was the salient signifier, while those in North America contend that it is sexual orientation, specifically “homosexual” vs. “non-homosexual”, which readers of my blog, and those familiar with the literature, know gives a strong signal / correlation with autogynephilia in MTF transsexuals.

In the graphs below, a higher score means more gender incongruent appearance (i.e. ‘readable’), while a lower score means more gender congruent (i.e. ‘passable’).

passingtransNow, looking at our earlier observation, do exclusively “homosexual” transsexuals pass better than “non-homosexual”?  For transwomen, the answer is a resounding “YES!”, with a large effect size (d=0.7).  Putting this into everday language, this is to say that the most passible of the non-androphilic transwomen are just barely comparable to the average androphilic transwoman.  Or another way of putting it, nearly half the androphilic transwoman pass better than nearly all non-androphilic.  Or yet another way of putting is that the least passible androphilic is the same as the average non-androphilic transwoman.

However, keep in mind that we know that many “late transitioners” misreport their sexual orientation because of Social Desirability Bias and Autogynephilic Pseudo-Androphilia.  From several studies we know that perhaps 38% report that their sexual orientation ‘changed’ from exclusively gynephilic to androphilic or bisexual. and that estimates of misreported sexual orientation means that from 20-40% of the self-reported androphilic group is in fact, non-androphilic, which would tend to pull the data toward the non-androphilic value.  Even with that possibility, the data still shows that androphilic MTF transwomen pass far better than non-androphilic.  The data also shows a greater range, standard deviation, which we would expect if 20-40% of the self-reported androphilic were in fact a mixture of the two populations.


Dr. Joy Shaffer and Kay Brown at ages 27 & 26.  Joy is non-androphilic, transitioned at age 21/22. Kay is androphilic, transitioned at age 17/18.

So what of our question about early vs. late onset?  Here again, early onset passes better.  But look closely at the data, 46% of the early onset group are androphilic.  If we hypothesize that the salient signifier is sexual orientation and NOT age of onset, then we would expect that the relative score for early onset would be intermediate between androphilic and both non-androphilic and late-onset (which is predominately non-androphilic at 79%).  And that indeed is what we see.  Further, one would predict that since late onset is predominately non-androphilic, that they would have the same level of passability… and indeed that is what we see again.  The data clearly supports the position that sexual orientation and NOT age of onset is the salient signifier, given the stronger signal.  That is to say, variation in the data is explained completely by sexual orientation and that the variation of passability with respect to age of onset is from the correlation between sexual orientation and age of onset.

It is clear that there is a mild correlation with sexual orientation and age of onset, with androphilic MTF transsexual more likely to report early onset (70% vs. 43%).  However, given clinical experiences with each, the meaning of age of onset is quite likely different.  If 43% of non-androphilic transwomen really did have an early onset… why do they all wait so long to socially transition?  The modal age is about 35 years and the average is about 40 years old compared to the 20 years old for androphilic.  I contend that retrospective age of onset is time shifted to an earlier age due to Social Desirability Bias AND to having a different internal meaning to the question.  For transkids (androphilic transwomen), the age of onset is demarcated by extreme somatic and social dysphoria, while for non-androphilic the demarcator is retrospectively found by their strong but vacillating autogynephilic desire for somatic transformation, but with little as yet stable social or somatic dysphoria.  As per Doctor and Prince, it takes considerable time for true gender dysphoria and cross gender identity to develop in non-androphiles / autogynephiles.

We are still left with an open question.  Why do androphilic transwomen pass so much better than non-androphilic?  Three possible hypotheses exist, 1) Having a truly earlier age of onset and social transition age, they experience less masculinization from endogenous androgens. 2) Self selection for passibility as they are motivated to fit into society better, being both physically and behaviorally extremely gender atypical (and not autogynephilically motivated). 3) Actually being, as a group, intrinsically more physically gender atypical.  (That is to say, that the etiological cause for their behavioral gender atypicality causes physical atypicality as well.)

Its also quite possible that any or all of these may be operating.  In fact, I strongly believe that all three are, in fact, operating.  MTF transkids do transition and obtain HRT at an earlier age.  They (we) do care and want to pass to better our lives.  And, from research into gender atypical children, it has been noted that gender atypical and dysphoric male children are considered more attractive than their gender typical male peers.  This ‘attractiveness’ is caused by hypomasculinity (masculine faces aren’t “pretty”).

Looking at the data for FtM transmen, there seems to be a small signal.  I would really like to see a study with more subjects, as this didn’t seem to be as statistically significant as we would like.  Even if real, the effect size is small.  However, we do have collaborating data from earlier studies that show that FtM transkids are judged to be more physically masculine than non-trans-girls.

(Addendum 9/10/2017:

There have been hints from a number of studies that there is a correlation between sexual orientation and subtle gender atypical facial physiognomy.  A new study just how strongly supports this observation.  Using a deep-layer neural net AI trained to categorize faces as heterosexual or homosexual, can differentiate between two faces, one of a heterosexual and one of a homosexual, of the same natal sex at 91% accuracy for males and 83% for females.  That is, the researchers in essence found that there is a sexual orientation dimorphism with an effect size of d=1.9 for males and d=1.4 for females.  This is an amazingly high effect size for both populations.  In fact, this is higher than the effects sizes found for passability.  Of course, I believe this is because many of the subjects have been incorrectly categorized, as I mentioned above.  But it could also be due to this study being restricted to the face and the passability study looking at one’s entire physique.  Note that the effect sizes for the sexes both agree in proportion, males being larger than females.  This adds more strength to the hypothesis that at least some of the cause of the difference in passability between the two types is native gender atypicality of the “homosexual” transsexual taxons.)

Further Reading:

Differences between androphilic vs. non-androphilic transwomen, passing, and transition decision making.


Tim C. van de Grift, Peggy T. Cohen-Kettenis, Thomas D. Steensma, Griet De Cuypere, Hertha Richter-Appelt, Ira R. H. Haraldsen, Rieky E. G. Dikmans, Susanne C. Cerwenka, , Baudewijntje P. C. Kreukels, “Body Satisfaction and Physical Appearance in Gender Dysphoria” Archives of Sexual Behavior
DOI: 10.1007/s10508-015-0614-1

Zucker KJ\, Wild J, Bradley SJ, Lowry CB., “Physical attractiveness of boys with gender identity disorder.” Archives of Sexual Behavior. 1993 Feb;22(1):23-36.

Stephanie A. Mcdermid, Kenneth J. Zucker, Susan J. Bradley, Dianne M. Maing, “Effects of Physical Appearance on Masculine Trait Ratings of Boys and Girls with Gender Identity Disorder” Archives of Sexual Behavior

Sari R. Fridell, Kenneth J. Zucker, Susan J. Bradley, Dianne M. Maing, “Physical attractiveness of girls with gender identity disorder” Archives of Sexual Behavior

Michal Kosinski, Yilun Wang, “Deep neural networks are more accurate than humans at detecting sexual orientation from facial images.”



Fun Reading:

All the Stars are Suns ebook completeSincerity Espinoza didn’t go looking for trouble, it found her. All she wants out of life is the chance to go to the stars but she is caught in a web of misunderstandings, political & legal maneuvering, and the growing threat of terrorist plots by religious fanatics. She has a secret that if found out too soon could mean not only her own death but the ruin of the hope for humanity ever going to the stars. But even amidst momentous events, life is still about the small moments of love, laughter, and sadness.   Available as an ebook at Amazon and Kindle Unlimited.

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Raising Children is a Sacred Trust…

Posted in Editorial, Transgender Youth by Kay Brown on December 8, 2015

Kay BrownParental Attitudes Towards Transgender Children

Every now and then, I check the stats on this site.  I am gratified by the growing number of readers over the past six years.  I also check the search strings that are used to find this site.  I am happy that parents of transkids find my site and this much needed information.  But I am usually saddened by the search strings.  These are the most common, in order of frequency:

“How to cope with transgender children”

“How to deal with a transgender child”

“How to manage a transgender kid”

“My child is transgender”

Do you see the problem?  The terms ‘cope’, ‘deal’, and ‘manage’ indicate that these parents see their child as a dissappointent, a burden, a problem.  One ‘copes’ with emotional loss and dissappointment.  One ‘deals’ with a burden.  One ‘manages’ a problem.

I’ve known dozens of other transkids (and former transkids / adults who were transkids).  Nearly every one of them spoke of how their parents had been dissappointed by them.  Even those whose parents eventually came to support them went through a period where their parents tried to deny that they were transkids.  Many were disowned by their parents.

But every now and then, but not nearly as often as I would like, I see this search string:

“How to help a transgender child”

Today, among several like the first three, I saw this gem:

“How to protect a transgender child”

Several years ago, my husband and I hosted a lovely young couple and their two children.  Their children were around three years old, fraternal twins.  One was ‘all boy’.  He wore his favorite T-shirt sporting an image of a bulldozer that read, “I like dirt”.  The other child was a sweet natured, feminine girl wearing a yellow flowered sundress.  She gave us an impromptu ballet recital in our front parlor.  Can you see where this is going?  That sweet mannered girl is male.

This young couple loved and celebrated their children.  Both of them.  They told me that they didn’t like attending support groups for parents of gender atypical / transgender children because the other parents saw their children as dissappointments, problem children, burdens.  The other parents would spend most of the time trying to convince everyone, including themselves, that they had done everything they could to cope, deal, and manage their children.  They were apolegetic about their child’s behavior and even of their own eventual acceptance of their child’s atypicality, having done everything they could to prevent it.

Which brings me back to the search string that I never see, but would dearly love to:

“How to celebrate my transgender child”

(Addendum 2/4/2016:  Banner Day!  Today someone used this search string, “loving your transgender child”)

(3/26/2016:  UGLY DAY!  Today someone used this search string, “things to say to comfort parents of a transgender”, as though having a trans-child were a terrible tragedy.



Fun Reading:

All the Stars are Suns ebook completeSincerity Espinoza didn’t go looking for trouble, it found her. All she wants out of life is the chance to go to the stars but she is caught in a web of misunderstandings, political & legal maneuvering, and the growing threat of terrorist plots by religious fanatics. She has a secret that if found out too soon could mean not only her own death but the ruin of the hope for humanity ever going to the stars. But even amidst momentous events, life is still about the small moments of love, laughter, and sadness.   Available as an ebook at Amazon and Kindle Unlimited.

Comments Off on Raising Children is a Sacred Trust…