On the Science of Changing Sex

Testosterone Poisoning Real?

Posted in Female-to-Male by Kay Brown on April 30, 2017

critical-thinkingHow T Makes Men Dysrational

Back in the early ’90s when I was staying home from work because of some bug, I recall watching daytime reruns of really dumb shows. I chanced upon a silly sitcom for ‘tweens where one of the plot elements was a math problem which was supposed to be challenging for the middle school students. It was a classic dual rate problem: How long it would take two boys washing cars if they did the next car together instead of separately.  As I was bored, I set up and solved the simple (to me) algebra problem during the next commercial break. I looked forward to seeing that I was correct.  As the show progressed, the kids were becoming more and more agitated that no one could solve it, not even the stereotypical “brain” of the class.  Only the stereotypical airhead girl (obnoxious portrayals) seemed to be immune.  At the climax of the show, no one has solved it, but the airhead… who states, “It can’t be solved.”  “Right!” the math teacher concurs.  WTF!?!?!  I think.  The “brain’s” head explodes.

I was dumbfounded.  I checked my work.  No, I could easily solve it.  No, it didn’t take a genius.  It was a very straight forward bit of algebra any first year high school algebra student could solve.   How could the writers, producers, stage crew, and actors not know this?  What the &^%$#@! were they doing telling their young audience; that it couldn’t be solved?

This episode (pun intended) stuck in my mind.  I couldn’t understand it until I learned of the phenomena of Dysrationalia, researched by Keith Stanovich.  It was a revelation.  But I never thought this topic would find it’s way to my blog here, not being related to trans issues (save perhaps as one possible explanation for the irrational denial of the two type taxonomy).  But, here it is…

High testosterone levels increase dysrationality.  Seriously.

In a recent study, healthy men were randomly given T gel or placebo gel to apply to their skin.  Hours later, their plasma T levels had doubled.  They then took on a series of cognitive tests buried within them were three “trick questions” that measure “Cognitive Reflection”, a subset of the Stanovich’s original seven dysrationality questions.  These three questions, mathematical in nature, are extremely easy, deceptively easy, in that unless one slows down and thinks, one will all too easily try to use irrational mental shortcuts that get the wrong answers.  The key to being rational is that another part of the brain double checks one’s thinking to spot this and says to one’s self, “hey, hold on, that type of thinking is flawed.”

The results were dramatic.  Those who had been given T got 20% more wrong answers than those given the placebo.  The difference was quite robust ( Cohen’s d=0.41 ).  High T levels seem to reduce the ability of the brain to spot irrational thinking processes.

This has implications for transmen as they begin and continue hormone replacement therapy (HRT) using testosterone, as transient high levels of T occur.  Transmen should be counseled on this phenomena and given cognitive tools to compensate.

Researchers should also look at the effects of androgen suppression in transwomen.  Does this effect go in reverse?  Does low T make one less prone to cognitive reflection errors?

Further Reading:

Rational and Irrational Thought: The Thinking That IQ Tests Miss


Nave, Gideon and Nadler, Amos and Zava, David and Camerer, Colin (2017) Single dose testosterone administration impairs cognitive reflection in men. Psychological Science . ISSN 0956-7976 .   http://resolver.caltech.edu/CaltechAUTHORS:20170428-091020875

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Posted in Brain Sex, Confirming Two Type Taxonomy, Female-to-Male by Kay Brown on July 2, 2016

critical-thinkingA new review paper has just been published on the current status of brain structure research in transsexuality.  Interestingly, it was submitted to the Archives of Sexual Behavior two full years ago.  This suggests that it went through a rather thorough peer review.  For myself, the first thing I do when reading a review paper is to see that the reference list is comprehensive to ensure that the authors aren’t cherry-picking.  In this case, they are not.  The paper looks to be very complete and scientifically honest.  You may wish to read it yourself, as it is not behind a paywall, thankfully.

The paper is written rather densely, with a great deal of information and discussion; so much in fact, that I will likely be writing several essays covering a number of topics from it.  At the high level, my regular readers will not be surprised at the primary conclusions drawn from the review, as I had already written about a fair number of the brain research papers.  The authors offer this chief conclusion at the end of the paper,

“The review of the available data seems to support two existing hypotheses: (1) a brain-restricted intersexuality in homosexual MtFs and FtMs and (2) Blanchard’s insight on the existence of two brain phenotypes that differentiate “homosexual” and “nonhomosexual” MtFs”

The review of all of the available brain structure research fully supports the Two Type Taxonomy.  In light of this, the authors recommend that future researchers take care to distinguish between the two types, lamenting that some studies in the review had not made this distinction, and further, that it is important that the control groups also be concordant with sexual orientation,

“The study of mixed samples implicitly assumes that transsexuals are a homogeneous group. This is far from the truth with respect to the onset of GD and sexual orientation.  …  These observations signify that control groups in studies of the transsexual brain must be homogeneous in regards to sexual orientation.”

The authors did find separate studies of androphilic “homosexual” MTFs and non-gender dysphoric gay men that used the same methods, such that a tentative comparison could be made,

“The only study on the CTh [cortical thickness] of homosexual persons that do not present gender dysphoria is by the Savic group (Abé et al.). If we compare this study with that of Zubiaurre-Elorza et al. on the CTh of homosexual MtFs, we see both studies report sex differences showing an F > M pattern in similar structures of the right hemisphere. But there is only one region, the pars triangularis, in which homosexuals and homosexual MtFs both present differences. However, these changes are in opposite directions. The pars triangularis of homosexual MtFs is thicker than in heterosexual male controls, while for homosexuals it is thinner than in heterosexual males. Thus, it seems that for transsexuals this region is feminized but demasculinized [i.e.: “different that straight men, but not in the heterosexual female direction” – K. Brown] in homosexual individuals. Interestingly, in both studies, the affected pars triangularis is in the right hemisphere. Nevertheless, confirming Blanchard’s prediction still needs a specifically designed comparison of homosexual MtF, homosexual male, and heterosexual male and female people.”

This is interesting, that there is a difference between gay men and androphilic transwomen?  But the right hemisphere pars triangularis of all things?  For left hemisphere dominant people, this region of the brain is believed to be involved in the understanding and production of prosody, emotionally nuanced speech modulation.  We know this because individuals who have serious lesions in this area have trouble with prosody.

For more information, read the Wikipedia page on prosody.

Before anyone gets too excited about the possible implications for a neurological marker for androphilic transsexuality that differentiates them from gay men, we need to note that the brain exhibits neuroplasticity.  That is to say, that like a muscle, exercise of particular skills causes the brain to increase in volume and neuron number in those regions used to supply that skill.  If this is about language and more particularly, about language production that imparts an emotional / sexual identity / gender identity through one’s voice, the difference in this part of the brain may be caused by experience and practice.

For more information, read my essays on feminine speech production and on voice recognition.

On the other hand, it just might represent a real difference.  We need more studies.


Guillamon, A et al., “A Review of the Status of Brain Structure Research in Transsexualism” Arch Sex Behav (2016). doi:10.1007/s10508-016-0768-5

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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.

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

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Shades of Grey…

Posted in Brain Sex, Confirming Two Type Taxonomy, Female-to-Male by Kay Brown on February 23, 2015

shrinking brainShades of Grey… Matter

We live in exciting times – At least scientifically.  We can now peer into the heads of transsexuals to see if their brains exhibit sexually dimorphic features that match their natal sex or their preferred gender.  Years ago, Ray Blanchard made a prediction, based on early evidence that there was a taxonic difference between “homosexual” and “non-homosexual” transwomen in sexuality, natural gendered mannerisms, age of transition, etc, that the former would show sexually dimorphic features in the brain that were shifted in the female direction while the latter would not, but would show features that were different than controls, but that they would not be sexually dimorphic features, and definitely not shifted in the female direction.  We now have yet more evidence that that prediction is correct, giving more weight to the two type taxonomy of MTF transsexuality, namely exclusively androphilic vs. autogynephilic.

The best evidence would be to use two populations of transwomen, one known to be exclusively androphilic and the other not, and test them for the same features, using the same type of measurement.  We now have that data for grey matter distribution in the brains of both types of transsexual.

In the earlier Savic and Arver paper, they compared grey matter distribution of 24 gynephilic transwomen, before HRT to that of heterosexual men and women.  (Remember, HRT itself causes a shift in sexually dimorphic features due to activational effects of sex hormones, and the lack of such hormones.)  The conclusion?

“The present data do not support the notion that brains of (gynephilic) MtF-TR are feminized.”

In the later Simon paper, they compared grey matter distribution of 10 exclusively androphilic transwomen, and 7 exclusively gynephilic FtM transmen, before HRT to that of heterosexual men and women.  The conclusion?

“Our findings support the notion that structural differences exist between subjects with GID and controls from the same biological gender. We found that transsexual subjects did not differ significantly from controls sharing their gender identity but were different from those sharing their biological gender in their regional GM volume of several brain areas, including the left and right precentral gyri, the left postcentral gyrus (including the somatosensory cortex and the primary motor cortex), the left posterior cingulate, precueneus and calcarinus, the right cuneus, the right fusiform, lingual, middle and inferior occipital, and inferior temporal gyri. Additionaly, we also found areas in the cerebellum and in the left angular gyrus and left inferior parietal lobule that showed significant structural difference between transgender subjects and controls, independent from their biological gender.”

The choice to explore only “homosexual” transsexuals in this study was informed by the researchers’ knowledge of the Freund/Blanchard taxonomy and of Blanchard’s prediction, as they explained,

“Both MTF and FTM patients were eligible for the study, but only those with homosexual orientation. The rationale for this choice was based on the Blanchard typology which considers two fundamentally different types of transsexualism: homosexual and nonhomosexual. Homosexual transsexual individuals are sexually attracted to the same biological gender, while nonhomosexual transsexual individuals are attracted to either the opposite gender or show no sexual orientation/attraction at all. According to Blanchard, homosexual transsexuals are usually younger at initial presentation of gender identity disorder and show more pronounced and frequent childhood femininity, as well as different anthropometric data. One might argue that mixing individuals from both transsexual groups in one study targeting the neurobiological background of transsexualism might bias the results by introducing heterogeneity in the sample. Thus, in our study, only homosexual transsexual individuals were included preventing our findings from the aforementioned bias.”

This points to growing recognition within the scientific community that the two type taxonomy is correct.  They went further, indirectly referring to the taxonomy and Blanchard’s prediction,

“In another study also limited to MTF transsexuals Savic and Arver, reported no “feminization” of any brain region with regard to structure. Nonetheless, certain brain areas (clusters ≥100 voxels) showed characteristic structural features in the transsexual group compared with both male and female control groups. Specifically, they found reduced thalamus and putamen volumes and increased GM volumes in the insular and inferior frontal cortex and in the right temporo-parietal junction (angular gyrus and superior temporal gyrus) in the transsexual group compared with both control groups. In our study, however only the angular gyrus (but in the left hemisphere) was affected among these areas, showing lower regional GM concentration in both FTM and MTF transgender subjects compared to controls, independent of their biological gender. When comparing the results reported by Savic and Arver to either our study or to other imaging studies in the literature of transsexualism, it has to be taken into consideration that their reported results were obtained from a solely nonhomosexual transsexual group of patients. The lack of real overlap between our and Savic and Arvers’ findings, despite the very similar methodology used, might at least in part be explained by the difference of the sexual orientation of the two samples.”

Truly, exiting times.


Ivanka Savic, Stefan Arver, “Sex Dimorphism of the Brain in Male-to-Female Transsexuals”

Lajos Simon, Lajos R. Kozák, Viktória Simon, Pál Czobor, Zsolt Unoka, Ádám Szabó, Gábor Csukly, “Regional Grey Matter Structure Differences between Transsexuals and Healthy Controls—A Voxel Based Morphometry Study”

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Child’s Play

Posted in Female-to-Male, Science Criticism, Transgender Youth by Kay Brown on February 9, 2015

critical-thinkingFor years, critics of transkids’ identities have made claims that transkids are either “confused”, “delayed”, or “pretending”.  Many papers describing feminine boys from the 1960’s would describe them as being “talented mimics”, explicitely taking the position that men and women, boys and girls, do in fact have in-born differences in behavior, mannerisms, and motor-movements, but that these feminine boys were NOT exhibiting natural behavior, but were consciously, or “subconsciously”, observing girls and women, and learning to “mimic” these behaviors.  Of course, those of us who were such and grew up to transition, have long begged to differ!

Today, we have a published paper that demolishes these notions.  At the core of the paper is the ability to determine implicit associations between concepts.  If you are not familiar with this tool, it may be useful to review the Wiki page on Implicit Association Testing .  One of it strengths is that it cannot be “faked”.  It is impervious to Social Desirability Bias or other impression management distortions.  It is also impossible for someone to be “pretending”, as the cognitive load to evaluate the test set-up, determine the “right” answer, etc. would create an obvious delay in the test.  Further, if a child were “confused” as to the meaning of sex and gender, there would be an obvious anomalous signature in the test results.

ImplicitThe study involved 32 transkids, ages 5-12, 12 FtM, 20 MTF, who have already transitioned full time, with the full support of their families.  This would obviously include “early onset” transkids.  However, and this is critical, we know, or at least suspect, that some of these kids will “desist” being gender dysphoric before puberty, if they follow the trend already seen in other studies, most especially the Steensma study from the Netherlands.  Yet, for all of that, the results of the study show that these kids are completely consistent in their implicit gender identity and preferences as their opposite sex, non-trans, controls and siblings.  They are NOT pretending, nor confused.

The folks who conducted this recent study are continuing their work, looking at these kids as they grow up.  They are looking for additional transkids to join the study.

Study on Gender Nonconformity in Children

Hi from the TransYouth Project at the University of Washington! We are researchers interested in gender development in children and have a new research project we are currently recruiting families for. The project aims to better understand gender development in gender nonconforming and transgender children.  Our new study takes 30-60 minutes and includes children ages 3-12. We are running the study all over the U.S. and Canada so please let us know if you are interested and we can let you know when we’ll be in your area. We are hoping to recruit gender nonconforming children as well as their siblings (where applicable). All data collected as part of this study are confidential. Payment is $10 per parent and $10 plus a small toy per child. There is an optional longitudinal component that we can tell you more about as well if you are interested. To sign up for the study, please visit: http://www.transyouthproject.org. If you have any questions, feel free to contact me, Dr. Kristina Olson, via email (krolson@uw.edu) or phone (206-616-1371). Thanks for considering being a part of this research or telling someone who might be!


Kristina R. Olson, Aidan C. Key, Nicholas R. Eaton, “Gender Cognition in Transgender Children“, Psychological Science

Thomas D. Steensma, Roeline Biemond, Fijgie de Boer and Peggy T. Cohen-Kettenis, “Desisting and persisting gender dysphoria after childhood: A qualitative follow-up study”

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Are Your Ears Burning?

Posted in Female-to-Male, Science Criticism by Kay Brown on January 19, 2015

critical-thinkingIt has long been hypothesized that prenatal or perinatal hormone levels influence sexually dimorphic behavior in humans.  The evidence from studies of people with Disorders of Sexual Development and in numerous animals studies lends strong evidence that this is true.  So it would seem natural that we should ask if sexual orientation and gendered behavior in otherwise phenotypically normal individuals could also have been affected by hormones.  The ultimate study would be one that longitudinally follows a large cohort of individuals from conception to adulthood, taking extensive hormonal assays while evaluating gendered behavior and sexual orientation.  The problems of doing such a study for transsexuality is obvious… the cohort would have to be in the hundreds of thousands to ensure statistically significant numbers of transsexual individuals were included.

Thus, researchers are interested in finding sexually dimorphic markers that record historical hormone environments.  That is to say, something that is an organizational and not an activational effect, preferably one that becomes fixed at the same period in prenatal development as organizational effects in the brain.  It must be something that is observable at birth and remains stable long enough to allow us to use it to retrospectively determine ones hormonal environment after we have found our gender atypical population of interest.

I’ve already blogged about one such putative measure, the 2D:4D ratio, which is mildly sexually dimorphic, and in at least some population has a recognizably large enough effect size that we can hope that we can use it.  Sadly, the results have been contradictory so far.  But despair not, another such sexually dimorphic marker is available, though it requires specialized equipment to measure.

In individuals with normal, unimpaired hearing, a curious effect is found in which our inner ears respond to external sounds with sounds of their own, which is known to be mildly sexually dimorphic, as described in the abstract from a recent paper out of Europe, the first known to explore this effect as a potential probe of the role of androgens in gender dysphoria,

“Click-evoked otoacoustic emissions (CEOAEs) are echo-like sounds that are produced by the inner ear in response to click-stimuli. CEOAEs generally have a higher amplitude in women compared to men and neonates already show a similar sex difference in CEOAEs. Weaker responses in males are proposed to originate from elevated levels of testosterone during perinatal sexual differentiation.  Therefore, CEOAEs may be used as a retrospective indicator of someone’s perinatal androgen environment.”

coeaeBefore we get too excited about this marker, we need to look at the effect size, with is quite small at only d=0.30 in the left ear and was better in the right ear at d=0.60.  You may recall that this is of the same order as the 2D:4D finger length ratios at d=0.63.  This is large enough to be useful, but only if enough subjects are available to achieve significant statistical power.  Sadly, this lack of enough subjects seems to be the case in this study.  Too bad, because there is a hint at some exciting results in that looking at a group of gender atypical and gender dysphoric children and teens, the natal males seem to show a shift in the female-like direction, but oddly, the natal females do NOT,

“In the present study, we retrospectively investigated possible organizational effects of prenatal androgens on CEOAEs in relation to gender identity. We found that boyswith GID had sex-atypical (hypomasculinized) emissions. Their mean response amplitudes, though, were not significantly different from either the male or female controls. Thus, boys with GID had an intermediate position between the sexes in terms of CEOAE response amplitudes. By contrast, girls with GID showed emissions in the same range as female controls.  Consistent with several earlier studies, sex differences in emission strengths were observed in the control group, with girls having significantly stronger emission amplitudes than boys. Our finding that boys with GID showed stronger, more female-typical emissions compared to control boys suggests that boys with GID might have been exposed to relatively lower amounts of androgens during early development. The effect sizes for the comparison boys with GID versus control boys were similar to those for control girls versus control boys, supporting the notion of a hypomasculinized early sexual differentiation in boys with GID.  However, considering the lack of statistically significant differences between the control boys and the boys with GID and the relatively small sample size of subjects with GID, this conclusion may still be premature and our results therefore need to be interpreted with caution. Furthermore, our findings did not support the hypothesis of an increased exposure to androgens in girls with GID during prenatal development. Though speculative, this might reflect that GID in girls does not develop under the influence of prenatal androgens or at least not during the same critical time window as when androgens exert influences over OAEs.”

This result is surprising, in that previous studies involving gay men and women, researchers saw the opposite pattern, in that gay men showed no shift from control men, but lesbians showed a shift from the female to the male response.  The most exciting times in science are when you hear, “That’s strange!”  This is one of those times.  Several possibilities exist.  This result could just be spurious, with not enough subjects to have seen the real signal.  It could be that there is an additional activational effect that occurs as children mature, that causes a shift for both gay men and gay women toward the masculine response.  We may be seeing the effect of heterosexual “tomboys” swamping out the FtM signal.  Or, we could be witnessing the first hint that there is a difference between transkids, both MTF and FtM, and conventionally gay men and lesbian women.  Time and additional studies will tell.


Sarah M. Burke, Willeke M. Menks, Peggy T. Cohen-Kettenis, Daniel T. Klink, Julie Bakker, “Click-Evoked Otoacoustic Emissions in Children and Adolescents with Gender Identity Disorder”  Archives of Sexual Behavior, DOI 10.1007/s10508-014-0278-2

Dennis McFadden, Edward G. Pasanen, “Spontaneous otoacoustic emissions in heterosexuals, homosexuals, and bisexuals” Journal of the Acoustic Society of America, http://dx.doi.org/10.1121/1.426845

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Winds of Change

Posted in Female-to-Male, Science Criticism, Transsexual Field Studies by Kay Brown on November 6, 2014

critical-thinkingIn a very recently published paper (not behind a paywall, thankfully) the issue of changes in self-reported sexual orientation in transsexuals over their lifetime is explored.   The paper has some interesting data… and some very, very problematic data.  One of the problematic data points was the surprising number of self-reported, putatively, originally exclusively androphilic MTF transwomen whose sexual orientation changed to something else.  But… there seems be something… well… fishy about the data.  Take a look at this table:

Initial sexual orientation and history of transition in MtF: N= 70
Orientation               androphilic        gynephilic        bisexual        analloerotic (asexual)
N =                               18 (25.7%)           36 (51.4%)       7 (10%)         9 (12.9%)
age  (SD)                     41.6 (16.4)          51 (9.6)             36(10.8)        47.9 (15.9)
Age of onset              7.2 (3.9)             11.6 (9.9)         11.7 (7.3)       14 (5.8)
first  counseling      32 (13.8)            42.6 (11.5)        31.3(8.7)       39(17)
Transition                 36.4 (10.8)        45.2 (9.6)          33 (7.7)          40.7 (12.1)
HRT                              31.1 (13.8)        42.8 (11.8)        31.9 (9.5)       41.1 (17)
SRS                               35.3 (14.1)        47.5 (10.3)        36.2 (9.3)      34 (12.7)

Do you see it?  Hint:  Compare the ages and ages of transition for the “androphilic” and “bisexual” groups.  Ummmm… sorry guys, that data disagrees with EVERY other study ever done.  The mean age of transition for transkids is closer to age 20.  This was seen in the Nuttbrock and Tsoi studies, in which half of the androphilic MTFs who had started HRT had done so as teenagers… here the average age is 31 years old???  How is it that the “bisexual” group had begun transition, on average, three and half years before the “androphilic” group?  And somehow the “androphilic” group had SRS before beginning transition???  WTF!?  NOT!  Something appears to be very wrong with the data.  The so called “androphilic” group in this study is essentially identical with the “bisexual” group.  So what’s going on?  Can we say, “Social Desirability Bias“?  It looks like there are no actual, genuinely, exclusively androphilic transwomen in this study sample… not even one.

The study suggests that five of the eighteen putatively originally androphilic transwomen had changed their sexual orientation to bisexual, gynephilic, or “unknown”.  I have another interpretation… these five individuals simply admitted to actually having always been non-exclusively-androphilic, finally acknowledge it, as they realized they didn’t have to keep up the pretense.

The rest of the study makes more sense, as six of the 36 of the originally gynephilic identified transwomen reported a shift to bisexuality and androphilia.  This sort of shift has been widely reported before.  Of course, these shifts are generally recognized to be a result of interpersonal autogynephilia,

“Autogynephilic MtF transsexual persons often report the fantasy of sexual intercourse as a woman with a man, that was repeatedly described as faceless and abstract. Yet this pseudoandrophilia has to be distinguished from genuine androphilia or homosexuality in MtF, or as Blanchard points it: ‘‘the effective erotic stimulus, however, is not the male physique per se, as it is in true homosexual attraction, but rather the thought of being a female, which is symbolized in the fantasy of being penetrated by a male. For these persons, the imagined – occasionally real – male sexual partner serves the same function as women’s apparel or makeup, namely, to aid and intensify the fantasy of being a woman’’. Similarly, one of our participants that formally reported a change of sexual orientation from gynephilia towards androphilia stressed that ‘‘I always wanted to experience sexual intercourse as a woman but I did not know what to do with my male body before the hormone treatment. I hated male bodies in general before’’. In this case a reported change in sexual orientation from gynephilic to androphilic can be attributed to autogynephilic fantasies.”

The more interesting data in this study is all about the FtM transmen, about which we have far fewer studies.  Of six originally androphilic FtMs, four of them experience a shift to being gynephilic during transition… and of the 33 originally gynephilic six experience a shift to being androphilic or bisexual.

“In gynephilic FtM a reported change of sexual orientation was less frequent. Six gynephilic FtM reported a change of sexual orientation towards bisexuality and androphilia in the present study. This may in part be explained by the fact that androphilic sexual behavior is complicated for FtM. Sex with male partners can induce intense gender dysphoria by being penetrated as a woman although feeling as a man. One participant in the study of Rowniak and Chesla stated that he didn’t like being ‘‘feminized in bed’’ and others used the description that they were unable to have sex with men ‘‘until they were a man’’. Thus in these 6 participants androphilia may have been the original sexual orientation that became possible only after transitioning. In this case we wouldn’t expect a genuine change of sexual orientation in these gynephilic FtM transsexual persons.”

I was friends with an FtM who stated exactly the same thing… that he ‘identified’ as and participated in the lesbian community because lesbians would let him be butch, but straight men wouldn’t.  As a gay identified FtM, he could finally be both butch and express his native androphilia.  He was in fact, autoandrophilic.  (See my essay on autoandrophilila in FtMs.)

It is gratifying that the authors recognize the weaknesses of their current study and make some recommendations for future studies,

“Self-reported sexual orientation studies have further been reported to be interfered by the fact that some persons do not answer the question truthfully. Some transsexual people for example may want to present themselves as particular feminine (MtF) or masculine (FtM) and thus ‘‘classical’’ transsexual persons.  Participants in the present study might have biased their reports on purpose or unwittingly towards a more gender-typical presentation. This may also involve worries on denial of sex reassignment surgery. We feel that attempts to minimize such worries are important in future studies. We also suggest that researchers should explicitly ask for autogynephilic and autoandrophilic sexual orientation.”

Further Reading:

Essay on Pseudo-Androphilia in Autogynephilic MTF transsexuals


Matthias K. Auer, Johannes Fuss, Nina Hohne, Gunter K. Stalla, Caroline Sievers, “Transgender Transitioning and Change of Self-Reported Sexual Orientation”

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Autistic Sky

Posted in Brain Sex, Confirming Two Type Taxonomy, Female-to-Male by Kay Brown on September 21, 2014

shrinking brainFor the past several years, evidence has been accumulating that there is a fairly high comorbitity between transsexuality / transgenderism and the autism spectrum.  Interestingly, and perhaps not totally surprisingly, among MTF transwomen, it appears to be exclusively found in the non-exclusively androphilic population.  This fits the Freund/Blanchard taxonomy and more importantly, Blanchard’s prediction that “non-homosexual” (with respect to natal sex) MTF transwomen would exhibit neurological / brain differences from control males but these differences would NOT be a shift toward female like brains.

Autism and autism spectrum disorders are found in four to five  times as many men as women.  There are a number of theories as to why this happens, including the rather intriguing “hypermasculine brain hypothesis”, in which a link between the slight differences between men and women, as groups, having different cognitive and social behaviors and the apparent similarity, or rather, exaggeration of these differences between men and women, found in those on the autism spectrum.  If autism is a form of hypermasculinization, it would not surprise us to learn that FTM transmen were more autistic-like than most women… and that is what one group of researchers found.

Using a 50 item, Likert scored, instrument called the Autism Spectrum Quotient (AQ), Jones, et Al., found that FTM transmen as a group, scored 23.2, higher than control women AND men!  This puts about half of the FTM onto the high functioning autism spectrum!!   (The lower AQ cut-off for ASD is 23.)  Non-exclusively-androphilic transwomen scored essentially the same as the control men, while exclusively androphilic transwomen scored essentially the same as the control women, and definitely (statistically significant: p<0.03 ) below both the control men and non-androphilic transwomen.

Group:               Men                  Women       FTM                 Non-Androphilic           Androphilic
.                                                                                                     MTF  N=129                   MTF N=69

Score (SD):       17.8 (6.8)        15.4 (5.7)     23.2 (9.1)        17.4 (7.4)                         15.0 (5.6)

The implication is clear, FTM’s are masculine, perhaps even hypermasculine, while the data also supports the Freund/Blanchard two type taxonomy for MTF transwomen.  In the discussion section of the paper, the authors remarked,

“Interestingly, with the 198 transwomen group, there were 6 individuals (i.e. 3%) with a diagnosis of AS. This rate is about 3 times as many as in the general population.”

These authors didn’t state what the sexuality of the six AS individuals were; but if they conform to the greater likelihood that they were non-androphilic, found in other papers, the incidence rate for such non-androphilic transwomen would be closer to five times the rate found in the general population, however, that is only about twice as high as that found in the male population.

(Addendum: 1/21/2017:  Looking at the data again, this time from the perspective of effect sizes with respect to men vs. women and non-androphilic vs. androphilic aids us in understanding how important this difference is.  First, the effect size between men and women is 0.38 a modest but still very noticable difference in the populations.  Now, let’s look at the diffence between non-androphilic and androphilic at 0.37, nearly identical to the difference between men and women.  So, lets compare the difference between men and non-androphilic tranwomen at 0.06 which is tiny.  And similarly, when we compare between women and androphilic transwomen it is only 0.07 which again is very tiny.  That is to say, these statistical tests shows that the difference between men and women is the same size as between non-androphilic and androphilic transwomen, while there is effectly no difference between men & non-androphilic and women & androphilic transwomen respectively.  That is to say, that non-androphilic transwomen are identical to men in general, while androphilic transwomen are essentially the same as women in general.  Further the difference between the two types of transwomen exactly matches the difference between men and women, which strongly supports the Two Type Taxonomy.)


Jones, et Al, “Female-To-Male Transsexual People and Autistic Traits”, J. Autism Dev. Discord. DOI: 10.1007/s10803-011-1227-8

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Drum keeps pounding… ♫♫

Posted in Brain Sex, Female-to-Male by Kay Brown on April 13, 2013

♫♫…rhythm to the brain…♫♫

shrinking brainData keeps coming in regarding brain imaging studies showing differences between MTF and FtM transsexuals and control males and females.  The question still remains, what does it mean?  Two studies, by two different groups, have measured the cortical thicknesses of transwomen before beginning HRT, to ensure that they are measuring potential organizing effects of endogenous hormones, or other effects, without the confounding activational effects of HRT.  However, the two studies looked at the two different MTF populations.  One, the Zubiaurre-Elorza paper examined only androphilic transwomen (N=18). Given that this group came from Spain, which, as Lawrence demonstrated, has a very low Hofstede Individualism index which is correlated with low percentage of gynephilic transwomen, these 18 were likely to have accurately reported their sexuality as exclusively androphilic.   While the Luders study, as an earlier study reported, examined both gynephilic (N=18) and self reported androphilic (N=6) transwomen.  Given that we know from many other studies of transwomen in high Hofstede Individualism societies, and the fact that the youngest of the Luders group was 23, we would expect that not all six of those who reported that they were androphilic were exclusively so.  In fact, I doubt that more than one or two at most is exclusively androphilic, if any.  Thus arises the question, can we use these two studies to get an early test of Blanchard’s prediction that “non-homosexual” transwomen would show brain difference from controls, but not a shift towards the female typical while the “homosexual” will show just such a shift?

First, some background, since I know that not all readers will be thoroughly up to date on the hypothesis being tested, nor the relevant data supporting it.  I recommend reading the FAQ on the is blog before continuing to read this blog entry, as a starting point.  Given that there is now mountains of data supporting the hypothesis that there are two types of MTF tranwomen, one autogynephilic (AGP) and non-homosexual (with respect to natal sex) and one that is non-autogynephilic and exclusively homosexual (HSTS); and that AGP transsexuals were behaviorally masculine since early childhood, and often even after transition and SRS, while HSTS transwomen had been remarkably feminine in behavior, and often in appearance, since early childhood, Blanchard made the prediction that brain studies would show that BOTH populations would be different than control males, but in different ways.  He further made the prediction that HSTS brains would be shifted toward the female morphology in sexually dimorphic areas of the brain, while AGP transsexuals would not.

This prediction is in opposition to the so called, “feminine essence” hypothesis, which is generally popular among AGP transsexuals, in which they posit that despite their obvious lack of naturally feminine behavior, they are still neurologically “female-like”, at least in some important way.

So far, the very limited data supports Blanchard’s hypothesis and NOT the “feminine essence” hypothesis.  Also so far, no formal study has been conducted that would specifically test these two hypothesis together.

I stated earlier that I didn’t believe that the Luders study group contain many exclusively androphilic (HSTS) individuals.  The reasons I believe this are several fold.  First, they collected most of their group by soliciting via transgender organizations.  As was shown in the Veale study on transsexual sexuality, soliciting through such organizations tends to reach only AGP individuals, as HSTS youth do not tend to be members of such.  Second is the age range of the study entire group.  The youngest was 23.  This would be very unusual for a group of that had a sizable portion of HSTS individuals, given that the median age of transition is 20 years old and the top end is typically 25 years old, and even that old is very rare.  If all six HSTS individuals were 23 to 25, this would be odd.  Also given that the mean age of the entire group is 45, which is a bit higher than the typical mean transition age for a group consisting of only AGP transwomen, this would suggest that there were not many of the total group that was in their early 20’s, certainly not six out of 24 individuals.  Thirdly, as Lawrence has shown, in two different study groups, significant numbers of individuals who claim to be androphilic are inaccurately reporting their sexuality.  Added together, I don’t believe that more than one or at most two, of the Luders study group was actually exclusively androphilic.  I suspect that none of them were.

As we explore the data from these two papers, we need to keep in mind that brains, like bodies, come in different shapes and sizes, more or less.  That is to say, although there are differences between male and female brains, on average, it is difficult to point to a part of the brain and say with absolute certainty, this is a male brain vs. a female brain.  Another thing to keep in mind, if we have a mix of two populations, both may have differences unique to each population… and that when mixed, both of those differences will be detected when we average the data, blurring and blunting the differences, but we should still be able to statistically see a signal in the data, provided we have enough data.

So, lets examine the data.  First, if we look at the high level view, it would appear that there are indeed differences between the control men and women and androphilic transwomen.

Zubiaurre Brain ScansIn general, female brains have thicker cortices (CTh), at least in some areas, as the comparison between male and female controls shows.  As we had expected, MTF  transfolk are different than male controls, but FtM are not that different from female controls.  The authors described the results thus,

“We have found that control females have greater CTh compared with control males in the frontal and parietal regions; in contrast, males have a larger putamen volume than females. With respect to the transsexual groups, we observed that FtMs have greater CTh compared with control males in the parietal and temporal cortices and did not differ from control females. However, FtMs have a larger right putamen than female controls. On the other hand, MtFs did not differ from control females in CTh and had greater CTh than control males in the frontal and occipital regions. In this group, no differences were found in the putamen. All these findings suggest that FtMs have a defeminized putamen, while MtFs have a feminized CTh.

With respect to the CTh of MtFs, we found that this group did not differ from female controls but did from male controls.  These findings suggest that MtFs follow the pattern of cortical thinning typically described for females. Whether the cortical feminization of MtFs depends on a differential cortical androgen receptor distribution, a different efficiency in the androgen receptors or other causes remains to be elucidated.  But what seems clear is that in MtFs the cortical developmental process is affected and follows the direction expected for females. This points out that the developmental approach could help to understand the etiology of transsexualism.”

Let’s compare these results with that of the Luders study, which is mostly (and perhaps entirely) non-exclusively androphilic, which being autogynephilic, Blanchard had previously predicted would show differences from control males, but not in the female like direction:

Luders Brain ScansAt first blush, we see that they are indeed, as predicted, different than control males.  Some areas of the cortices are thicker, but not the same regions as control females nor androphilic transwomen.  So, it would seem unlikely that these brain difference are caused by a feminization of the brain, given that the regions are not those found in control females.  But what does cause these particular differences?  While we might be tempted to conclude that this is caused by autogynephilia, it could also be caused by another attribute that is common in this population, higher IQ.  It has been noted that higher IQ is correlated with thicker cortices.

So where to do we go from here?  This visual comparison of the two studies can only be described as tentative.  But the need for such comparisons are clearly understood by these researchers, as the Zubiaurre-Elorza paper explained,

“On the basis of chromosomal sex and behavior, Blanchard and co-workers (Blanchard et al. 1987, 1989, 1996; Blanchard 1989; see also Smith et al. 2005) have proposed the existence of 2 types of MtFs: 1) MtFs that are attracted to males (“homosexual” transsexuals in Blanchard terminology), and 2) MtFs that are attracted to women (“heterosexual” transsexuals according to Blanchard). Further, Blanchard (2008) hypothesized that homosexual MtFs would differ from heterosexual males in brain sexually dimorphic structures, while in the heterosexual MtFs, the differences might not implicate sexually dimorphic structures. More recently, Cantor (2011) has noted that our findings on the white matter microstructure of (homosexual) MtFs (Rametti, Carrillo, Gómez-Gil, Junque, Zubiarre-Elorza et al. 2011) and that of Savic and Arver (2011) on the cortical volume of (heterosexual) MtFs would support Blanchard’s hypothesis. In the present report, we studied MtF transsexuals erotically attracted to males that show a feminization of CTh but not in the putamen.  …  Consequently, to verify Blanchard’s hypothesis would require a specific design that is beyond the scope of the present study.”

For more essays on trans-brains see Brain Sex.


Eileen Luders, et al., “Increased Cortical Thickness in Male-to-Female Transsexualism”
Journal of Behavioral and Brain Science, July 2011

Leire Zubiaurre-Elorza et al, “Cortical Thickness in Untreated Transsexuals”
Cerebral Cortex, August 2012

Katherine Narr, et al., Relationships between IQ and Regional Cortical Gray Matter Thickness in Healthy Adults
Cerebral Cortex, November 2006

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Curiouser and Curiouser…

Posted in Female-to-Male, Science Criticism by Kay Brown on February 18, 2013

… said Alice.

critical-thinkingIn a recent paper exploring the sibling sex ratio and birth order of transkids, several interesting new biodemographic findings were disclosed.  First, the already known surplus of older brothers of MTF transkids was observed, along with the fraternal birth order effect of having more older brothers than sisters.  But, curiously, these transkids also had more younger brothers than sisters!  The reason this is so startling is that we have no plausible conjectures on how this could come about, as we do the fraternal birth order effect.

Another curious item is that FtM transkids are more likely to be only children than one would expect by chance.  Blanchard does offer a possible conjecture that this may be an immune response, leaving the mother unable to conceive again.

This new finding in MTF transkids is further evidence that there may be more than one biological mechanism at play.

But to me, the most curious thing to note in this paper is the actual paper, who wrote it, and how it was edited.  It has the feel of having had sections written by different authors, who habitually use different terms for the same phenomena and populations.  As I had written in an earlier essay, those in North America preferred the term “homosexual transsexual” and those in the Netherlands preferred “Early Onset” transsexual.  This paper was co-written by Ray Blanchard, from North America, while the rest were from the Netherlands.  It would appear that both formulations were used in this paper, starting with “early onset” in the title then using “homosexual” in the abstract:

Several sibship-related variables have been studied extensively in sexual orientation research, especially in men.  Sibling sex ratio refers to the ratio of brothers to sisters in the aggregate sibships of a group of probands. Birth order refers to the probands’ position (e.g., first-born, middle-born, last-born) within their sibships. Fraternal birth order refers to their position among male siblings only. Such research was extended in this study to a large group of early-onset gender dysphoric adolescents.  The probands comprised 94 male-to-female and 95 female-to-male gender dysphoric adolescents. The overwhelming majority of these were homosexual or probably prehomosexual.  The control group consisted of 875 boys and 914 girls from the TRAILS study. The sibling sex ratio of the gender dysphoric boys was very high (241 brothers per 100 sisters) compared with the expected ratio (106:100). The excess of brothers was more extreme among the probands’ older siblings (300:100) than among their younger siblings (195:100). Between groups comparisons showed that the gender dysphoric boys had significantly more older brothers, and significantly fewer older sisters and younger sisters, than did the control boys. In contrast, the only notable finding for the female groups was that the gender dysphoric girls had significantly fewer total siblings than did the control girls. The results for the male probands were consistent with prior speculations that a high fraternal birth order (i.e., an excess of older brothers) is found in all homosexual male groups, but an elevated sibling sex ratio (usually caused by an additional, smaller excess of younger brothers) is characteristic of gender dysphoric homosexual males.  The mechanisms underlying these phenomena remain unknown.

The use of the term “homosexual” has often bothered many transsexuals, both autogynephilic and non-autogynephilic alike… but apparently it bothered at least one of authors of the paper as well,

(instead of ‘‘homosexual’’ transsexuals, we will refer to male-to-female transsexuals sexually attracted to men as androphilic MtFs, and to female-to-male transsexuals sexually attracted to women as gynephilic FtMs)

While I applaud the sentiment of using language that is more sensitive to the sensibilities and personal identities of transsexual people, the effort here loses its intended effect since all such males are still called “boys”, and such females are called “girls”, largely defeating the purpose.  Further, the authors simply did not maintain the usage of “androphilic” in preference to “homosexual” as later in the paper they write,

It was reasonable to assume that all or nearly all of the early-onset gender dysphoric boys in this study were, or would be, homosexual, and that nearly all of the control boys were, or would be, heterosexual;

So, it would appear that the final editor failed to clean up the language of the paper to make it consistent with a ‘politically correct’ terminology.  But this failure also allows us to unite the terms, making this paper a ‘Rosetta Stone” of research papers:

Homosexual = Androphilic (or Gynephilic for FtM) = Early Onset

Thus, this paper helps spell out, in an unambiguous manner, that the researchers are indeed talking about the same populations, and that there is now universal agreement that the Freund/Blanchard typology is correct.


Sebastian E. E. Schagen, Henriette A. Delemarre-van de Waal, Ray Blanchard, Peggy T. Cohen-Kettenis, (2012) “Sibling Sex Ratio and Birth Order in Early-Onset Gender Dysphoric Adolescents”

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