Gender Identity Disorder Information

Medical Research for a Physical GID Cause

Most laypeople tend to view the concept that Gender Dysphoric individuals are "born" to the condition with some skepticism. This is only natural, since the very nature of the condition manifests itself as a perceptual (and therefore appearing to be only mental) disorder. The classification of Gender Identity Dysphoria (GID) within the International Classification of Diseases-10 (ICD-10) and Diagnostic and Statistical Manual of Mental Illnesses (DSM-IV) serve to support the belief that the transgender condition is a mental illness[1]. Much of the reasoning, however, for categorizing GID as a "Mental Illness" is based in science and psychology that is now decades old - beliefs which are being overturned by current research.

It has long been known that "floods" of various hormones are instrumental in the development of a fetus. What remains a vigorous area or research is to determine exactly what effects what hormones have on virtually every structure within the developing fetus. Large scale sexually differentiated structures are the easiest to observe, and the general effects of various hormones on gonadal structures have long been known. However, microstructures such as clusters of neurons in the brain, have proven to be much more difficult to observe. Coupled with that is the fact that the precise functions of neurons in brain is a field of study still in its infancy. Again, only large scale structures are known with very generalized concepts about the functions of those structures. Nevertheless, new research has shed light on the closest thing we have to "proof" that GID has an underlying congential cause.

Biologically, all fetuses start out the same, whether they will ultimately develop into male or female, the fetus contains a structure that has four ducts that can develop into male and/or female genitalia. The determining factor for "normal" development is the presence or absence of a "Y" chromosome. [ I say "normal" because there are numerous deviations from the XX/XY karotypes ] Generally, if the Y chromosome is not present, the fetus will develop as female, with enzymatic signals sent out for "floods" of Estrogenic hormones and Mullerian Hormone (which causes the Mullerian Ducts to develop into female genitalia). Without a flood of Testosterone, the other two ducts do not develop into testes and the tissue is reabsorbed. If there is a Y chromosome present, it sends out "enzymatic signals" during the pregnancy for a number of "Male" hormones. These include Androgen, Testosterone, and Mullerian Inhibiting Hormone. Testosterone is the best known to laypeople and is believed to be primarily responsible for the development of two of the ducts into testes, while the Mullerian Inhibiting Hormone prevents the other two ducts from developing into ovaries - the other ducts whither and the tissue is reabsorbed by the fetus. Androgen, it is believed, is primarily responsible for structural differentiation of neurological tissues. Because of this, Androgen is sometimes said to "hard wire" the brain to process as "male." [2] Of course there are numerous, well-documented cases where this "normal" process is interrupted or deviates, resulting in children born with Klienfelter's Syndrome, Intersexed (formerly known as "Hermaphrodites"), Turner's Syndrome, Down's Syndrome, and so on[3, 4, 5]. The deviations that cause easily observed physical deformity or mental inhibition are most readily diagnosed. However, milder forms of deviation often go undetected, sometimes for the individual's entire life. The mechanisms that cause such deviations are varied and mostly unknown, they result from genetic errors, susceptibility, environmental toxins, maternal stress, malnutrition, drugs, radiation, and probably a host of things that haven't yet been discovered.

Research carried out in the mid-1990's may have discovered just such a previously "undetected deviation" in the brain structures of transgender individuals. In 1995 the Journal Nature [6] reported on the findings in Holland concerning an area of the brain called the bed nucleus of the stria terminalis (BST) region and its put it forth as a possible explanation for Gender Identity Disphoria. The BST region had long been believed to influence sexual behavior, and is known to be larger in male vertebrates, which was why the researchers compared the brains of six transsexuals to the brains of non-transsexual men and women. Although the sampling was small, the BST regions in all six transsexuals were closer to the average size observed in female brains. [I should note that there have been similar comparisons of the size of the BST region between known homosexual and heterosexual men that found them to be comparable. I could find no references to studies comparing the relative size of BST regions in known homosexual and heterosexual women, however ]. The next challenge came in determining if the size of the BST region could be altered post-natally[7]. Tests performed on laboratory rats and primates have subsequently determined that the size of the BST region is determined in utero by the presence or absence of Androgen and is not affected by hormones after birth. The BST region is basically part of the Hypothalmus, which is part of the "primitive" brain and is known to be responsible for regulation of autonomic functions, hormone production, and sexual behavior. In laboratory animal tests, where normal fetal development was purposely altered, male subjects have been observed exhibiting female mating behaviors. Upon examination of the BST regions in these animals, the male brains more closely resembled those of typical females. As this has been tested and shown among primates, it is reasonable to believe that the same processes and results would be observed in human subjects as well.[8] Of course, ethically, such human trials can't be done and researchers must rely on data collected from the population. There are two factors that are impeding human research on the subject. One is that human beings have complex sexual social behaviors that do not often tolerate deviations from the norm (unlike with animal subjects, where homosexual mating behaviors have not social or moral constraints). Transgender individuals will often conceal their true nature and even act opposite to their own instincts as a method of self-preservation. It therefore becomes difficult to identify a significant portion of such individuals and gather data. Even if individuals are identified there is the second problem - the BST region currently must be examined post-mortem by dissection of the brain. Clearly this would be an easier hypothesis to prove if researchers were dealing with a society as uninhibited as the animal kingdom and also had a non-invasive method of observing the BST region in living subjects.

UPDATE 5 May 2002:

Another study researching the BST region has confirmed that the concentration of neurons in transsexual males is within the observed average female range, while heterosexual and homosexual males both had larger nuron counts in the BST region. Furthermore, supporting evidence that this region is unaffected by post-natal hormone levels was observed.[u1]

Another new study, conducted in 2002, discovered an unexpected finding: the BST region in human beings does not become significantly sexually dimorphic until adulthood. This was unexpected because it was not observed in lesser mammals. While some people believe this new study has "dealt a serious blow" to the assertion that the BST region is a significant factor in determining transsexuality, I would beg to differ. The researchers themselves conjectured that neonatal hormone levels could STILL affect gender identity by simultaneously producing changes in BST "synaptic density, neuronal activity, or neurochemical content" that might not occur early in life, but come to fruition during adulthood. No studies have yet been done to determine if exposure to hormones early in life may affect how the BST becomes sexually dimorphic, but previous studies seem to indicate that, once the region has already developed in adulthood, anti-androgens or supplemental hormones have no effect on altering BST size or structure.[u2]

While it appears that the BST region of the brain is a very important contributor to "Gender Identity," it is by no means the ONLY part of the brain researchers are exploring. Some research is also looking at the effects hormones have elsewhere in the brain, for example a number of Androgen Receptors have been observed in the Hippocampus of rats - and area that is associated with learning and memory, not sexual behavior.[9] It is currently unknown why it would be important for that region of the brain to recieve Androgen. In other research, scientists are studying the forebrain projections that product the neuropeptite "vasopressin." The density of these projections is greater in male brains than in female brains, and their activity is known to be linked to gonadal hormone production. However, even in cases of castration it takes months for the vasopressin to clear from the neural projections.[10] It is believed that vasopressin is partly responsible for male aggressive behavior and possibly contributes to libido. This may explain why sex offenders who are castrated do no immediately become less agressive or aroused, it may also help to explain the "shift" in sexual oriention experienced by many transsexuals usually months after they have had a bilateral orchiectomy. It is also believed that male hormones may be responsible for other, broader, changes in brain development. Male and female brains have both been observed "processing" under Magnetic Resonance Imaging. One of the most striking differences was that language skills appear to be centered in a specific region of the male brain, while language processing was observed to involve several areas of the female brain - including the visual cortex. There also appears to be more cross-hemispheric communication in the female brain. Science is well on its way to proving some of the long standing beliefs about the differences between the ways men and women think. Some of it appears to have been determined ("Hard Wired") prior to birth, while other things are more "plastic" in nature - effected by hormones or other environmental influences.

The bottom line: Gender Identity Dysphoria is NOT a mental problem and therefore psychotherapy will not make it "go away." It is a PHYSICAL CONDITION, the cause of which cannot be altered by any known methodology. Individuals with GID are often in need, however, of some form of therapy to deal with the SOCIAL problems that often go hand-in-hand with the condition. Those problems, though, are caused by something external - namely a society that will not accept the preferred gender identity of the individual. This is a problem FOR the transgender individual and a problem OF society that requires either better coping mechanisms for the individual and/or a more tolerant social environment.

Medical Research for a Physical GID Cause Page 2

The following article pertains to research performed in the United Kingdom concerning the thought patterns of gays and lesbians as compared to heterosexuals. This research might also be applicable to many intersexed and transgendered people in that it provides stronger evidence that there is a neurological difference between the brains of heterosexual people and their non-heterosexual counterparts. Of particular note is the statement that says these differences in the brains are attributed to hormone levels during the first trimester of development.

Gays and lesbians have 'gender-bender' brains
25/03/2003 - 6:00:24 pm

Gay men and lesbians have gender-bending brains that contribute to their effeminate and “butch” stereotypes, it was claimed today.

A new study has found that gay men really do think like women, while lesbians show a similar affinity with men.

In tests, scientists found that gay men excelled at mental tasks women generally perform better than men, but were not so good at tasks traditionally seen as “male”.

Similarly, lesbians did as badly as heterosexual men in a test geared to get the best out of women.

The traits seem to be “hard-wired” into the brain before birth by varying levels of exposure to the male hormone testosterone, say scientists from the Institute of Psychiatry in London.

Men are generally better than women at spatial perception – the ability to mentally reposition shapes and objects and judge the orientation of lines.

It is for this reason men despair at the apparent ineptitude of women trying to read maps and park cars.

Qazi Rahman and Glenn Wilson conducted a series of neurocognitive tests of spatial skill. They found that gay men performed less well than heterosexual men, but matched the ability of women.

But gay men performed better than heterosexuals and as well as women at remembering the locations of objects in an array.

In several language tests, traditionally a female strong point, gay men did as well as heterosexual women. Lesbians, on the other hand, performed the tests as poorly as “straight” men.

Dr Rahman said: “Because we know that performance on these cognitive tests depends on the integrity of specific brain regions, the differences implicate robust differences between the brains of homosexual and heterosexual men and women and suggest that hormonal factors early in development (probably during the 1st trimester of pregnancy) produce these differences.”

The findings are published in a series of articles in the journals Neuropsychology and Psychoneuroendocrinology.

They may help explain why gay men and lesbians often suffer mental health problems quite different from those of heterosexuals, the authors claim.

Dr Rahman said: “The fact that gay men and lesbians show cross-sex shifts in their brain functioning might also be related, partly, to the cross-sex shifts in their presentation of certain mental health problems, such as higher levels of anxiety disorders, depression and eating disorders (found more in women) in gay men.

“Unravelling variations among groups of people in brain function is becoming an important area for research in human mental health, and a thorough scientific understanding of the biological and social factors which shape human sexual orientation is necessary so we can begin to tackle the mental health problems that gay men and lesbians may suffer from.”

The researchers also found that gay men and lesbians both had longer ring fingers relative to their index fingers than heterosexual men and women.

Relatively long ring fingers are a sign of exposure to elevated levels of the male hormone testosterone in the womb.

[Editors Note: The length of ring fingers as an indicator of testosterone exposure in the womb is disputed and unproved - though it is often stated as fact by the press, it is only a THEORY]

The findings supported the idea that high, not low, testosterone levels in men produce shifts in sexual preference.

But the evidence suggested that the testosterone levels involved were not high enough to be damaging.

This indicated that homosexuality was a normal biological phenomenon, and not the result of biological fault.


Evidence Gender Identity IS Genetic!
Mon October 20, 2003

California researchers at UCLA have published important new finding in the Journal Molecular Brain Research which repudiates the concept that homosexuality and transgender identity are a choice.

"Our findings may help answer an important question -- why do we feel male or female?" Dr. Eric Vilain, a genetics professor at the University of California, Los Angeles School of Medicine, said in a statement. "Sexual identity is rooted in every person's biology before birth and springs from a variation in our individual genome."

Since the 1970s, scientists have believed that estrogen and testosterone were completely responsible for sexual differentiation of brain structures. Recent evidence, however, indicates that hormones alone cannot explain everything about the differences between male and female brains.

The experiments were carried out on laboratory mice using two genetic testing methods. The researchers compared the production of genes in male and female brains in the embryonic mice which occurs in gestation long before the animals develop sex organs. The basic genetic principles are so fundamental to the process of sex differentiation that the results are believed to be directly applicable to human beings. The research team identified 54 genes produced in different amounts in male and female mouse brains, prior to hormonal influence. Eighteen of the genes were produced at higher levels in the male brains; 36 were produced at higher levels in the female brains.

It is already an established scientific fact that male and female brains differ in a number of measurable ways both anatomically and in function. The scientists plan to undertake additional studies to determine the role for each of the 54 genes they've identified.

Some physicians are hopeful that the UCLA discovery will provide them with a better means of determining the "base sex" of children born with ambiguious genitalia - using the genetic findings as a factor in surgical gender assignment decisions for such infants.

Realistically, though, there will likely still be a bias toward female gender assignments because the surgical procedure is easier to perform. Statistics indicate doctors choose erroneous gender assignments for intersexed children at least half the time. Without surgical advancements making assignment as male equally feasible the findings of this research are unlikely to greatly affect the trend of surgical misassignments. Intersex advocacy groups maintain that such surgery is, by and large, medically unnecessary anyway and see no great benefit in the addition of one more factor for surgeons to take into consideration when considering performance of a surgery that many intersexed people believe is simply "mutilation" of a defenseless infant for no reason but cultural bias dictating individuals be either "male" or "female."

As for transgendered the research provides yet more evidence their gender identity are not a "lifestyle choice."

"Our findings may explain why we feel male or female, regardless of our actual anatomy," said Vilain. "These discoveries lend credence to the idea that being transgender --- feeling that one has been born into the body of the wrong sex -- is a state of mind.

[source article at Reuters. Editorial note: The prevelence numbers they give for intersex births appear to be incorrect]

Some of the References I consulted in compiling this included: