How valid is current transsexual scientific research?

[keriB]

Posted this on my blog, thought it may be of interest here....

I'm in the process of finishing up research on my neuro paper, which focuses on dimorphism of the human brain between the sexes, with a potential tie-in to the biological basis of transsexuality.  Interestingly, one item I uncovered relates to trans scientific research.  One study found that, over time, administration of masculinizing or feminizing hormones to genotypical males and females seeking to change to their target, i.e. opposite, sex, does in fact physically alter brain size by volume measurements.  For Male to Female trans, the brain feminizes and becomes smaller, while for Female to Male, it increases in size.  What seems known are these purely volumetric statistics; what are not known is if a dramatic increase in estrogen or testosterone leads to a "re-wiring" of the brain and a differentiated brain functionality, as identified in numerous studies between males and females.

But here's my curiosity:  although there truly is a dearth of scientific research with regard to the constituent causes of transsexuality, those studies that do exist - including the recent androgen receptor study completed last October - utilize transsexual individuals already affected by hormone therapy.  If hormone therapy has been found to affect brain size by masculinizing or feminizing the brain to typical measurements, then this would seem to devaluate all studies of brain differentiation in trans folk, as performed in today's laboratories.  What really needs be done is to establish a proper research group prior to the beginning of HRT, conduct brain volume analyses and other measurements pre-HRT, and then conduct the same measurements at definitive time periods into HRT therapy.  Only in this light can we accurately measure any potential brain volumetric differences in trans-identified persons relative to their projected target sex.

While I am a big believer in the theories of biological causes of transsexuality, given that hormone administration has been found to alter brain size from masculinization to feminization and vice-versa, I must view current research methods as potentially fatally flawed in this regard.  Clearly, greater research is needed in this area, with the stated goal of developing a research population as early into the process as possible.

Interesting creatures, we TG/TSs' are.... 

[mina.magpie]

Hey Keri, I'm not allowed to post a link, but I did an essay about this not too long ago. It's up at my blog if you'd like to have a look.

Specifically, the study you're referring to doesn't invalidate the original research on transsexual hypothalamus .. es/i? being structurally similar to that of the identified-as gender. The original zhou study was criticised for not having control populations, but they did a follow-up study later on that included MtF and FtM individuals who had never transitioned, so their brains had never been exposed to HRT.

Mina.

[keriB]

Actually there is the Zhou study where one of the populations was a hetero male who never undertook HRT as part of their study base, but I refer generally to most research I have read on the subject.  While I haven't specifically read the second Zhou study, even the recent Hare study of last year states that "almost all" of the participants were on HRT. I'll check that out though, but it does seem nonetheless that the populations represented in the overwhelming majority of these studies are or have been undergoing HRT.  Thanks!

[mina.magpie]

The Hare study on polymorphism of the androgen receptor right?

That was a study on the genetic level, and hormones can't rewrite your genetic code. Specifically, the study found that transsexual people have a longer repeat-sequence on the AR allele.

Our genetics are fixed at conception. While this only shows a statistical synchronicity between this gene-sequence and transsexuality rather than a cause-effect relationship, it does seem to me to conclusively prove that we are different right from the moment we start out - definitely pre-natal.

Mina.

[Soapyshoe]

I've done some cursory research on transexuality just reading forum posts and blogs that summarize the research on transexuality.  I have a background in psychological research, so here's my evaluation:

1. There's a fairly large consensus that "the cause is biological".  In other words, transexual people have different brains, and those brain differences are likely caused by some hormonal or biochemical imbalance that occurs in the womb between weeks 12-16 or something like that.

2.  I have yet to see any research examining personality traits.  The "transexual" population is really the population of TRANSEXUALS WHO ARE OUT OF THE CLOSET.  It's fairly easy to imagine that a LARGE subset of the transexual population is and will forever remain "in the closet."

3. Transitioning in the only known cure for gender dysphoria and gender identity disorder.


My take on this stuff:
Saying that "it's in the brain" is nothing more than a tautology.  This explanation completely ignores a person's life-long social and chemical environment, his/her family life, personality traits, society in which the individual lives, etc. etc.  In addition, the individual typically must have outside assistance to come out of the closet and be found for research. 

There's a sweeping assumption that the transexual population is mentally ill and should be classified thus.  I strongly disagree with this.  Is it not possible for a perfectly healthy individual to desire to become a member of the opposite gender/sex?  Are we so opposed to the idea of self-determination that it's inconceivable that automatically assigned gender roles won't make some % of the population unhappy and cause them to want to change that role?

Science attempts to answer the question, "What causes transexualism?" as if some kind of definitive answer can be given.  It's like asking, "What causes some people to want to be rockstars."  While certain correlational research can be done which predict likelihoods, I think attempting to come up with a causal model is simply not worthwhile.

I like to think of transexualism as more of a process than "A causes B".  Something like:
1) An individual must first experiment with their gender role at some point in their life.  Transexualism cannot occur without this step.
2) They either come to internalize their assigned gender role, fail to acquire an internalized gender role, or internalize the opposite gender role.  Many people with GID or GD report internalizing the opposite gender identity at a young age.  Crossdressers seem to internalize the opposite gender role later in life, typically during adolescence.
3)  Society provides feedback to the individual about their gender role - if there is a conflict, the individual must seek to resolve this conflict via changing their belief about their gender, seeking help, etc. etc.
4) If the individual perceives transition to be a possibility, then there is a high likelihood that the individual will transition to a more appropriate lifestyle.

This is similar to the "14 stages" listed in another thread.