Archive for the ‘Science’ Category

A recurrent theme I’ve observed lately on trans blogs is the mis-application of Harry Benjamin’s Sex Orientation Scale (S.O.S). This scale was published in 1966 with the release of Benjamin’s groundbreaking book The Transsexual Phenomenon.

With a few significant corrections (e.g. later researchers have noted that sexual identity and sexual orientation are certainly not as closely correlated as Benjamin’s initial scale implied), I think the scale holds up surprisingly well. But it doesn’t hold up well at all in the case of people who want to use it for purposes divorced from Benjamin’s intent.

The S.O.S. was developed to address the need for a diagnostic tool which accounted for a group which, at the time, was entirely unrepresented in the medical literature. Previously when seeking professional treatment, transsexuals had been (mis)classified as either homosexuals or transvestites and (mis)treated accordingly. Benjamin wanted to call out, in practical terms usable in clinical practice, a more suitable set of guidelines for accurately diagnosing and effectively treating transsexuals.

He knew it wasn’t a perfect tool – in fact he took pains to point out some of its known flaws. Here is a telling excerpt from Benjamin’s introduction of his S.O.S (all emphases below are mine):

“The following chapters will make use of the types from I to VI in relating case histories and in establishing a diagnosis of the respective patients. Referring to Table I will then enable the reader to get a somewhat clearer picture of the particular individual and his or her problem. It should be noted again, however, that most patients would fall in between two types and may even have this or that symptom of still another type.

Or, in laymans’ terms, these are approximations. They’re intended to help physicians establish patient diagnoses. Don’t expect any single individual to fall neatly and perfectly into any of these types. They’re intended as practical guidelines, not hardbound rules.

He goes on to say:

“It has been the intention here to point out the possibility of several conceptions and classifications of the transvestitic and the transsexual phenomenon. Future studies and observations may decide which one is likely to come closest to the truth and in this way a possible understanding of the etiology may be gained. If this etiology should ever be established through future researches, classifications may have to be modified accordingly. In the meantime, the S.O.S. may serve a pragmatic and diagnostic purpose.

Layman’s translation: This ain’t gospel. It’s a work in progess. I’m relying on you – medical professionals – to keep this thing in harmony with the best available evidence. I hope you find it useful. If not, please make it better.

Here’s a quick flowchart showing Benjamin’s message about the purpose of the S.O.S.

Another item of note: Benjamin didn’t put much stock into the whole “early” versus “late” transitioner when it came to his standards. And he most definitely did NOT see these types as something any given patient must fulfill to the letter from initial presentation through final treatment. He observed patients initially diagnosed as one type who dramatically shifted to another over time, based on the totality of the evidence. He accepted this as a natural part of the diagnostic process.

Unlike less reputable researchers into transsexual lives, Benjamin didn’t assume that a patient was a liar for revealing something which challenged his preconceptions. He always assumed his own understanding of all the intricacies of how this condition affected individual lives to be incomplete.

Benjamin makes it pretty clear how he himself used these standards in relating examples of three different types of transsexuals. One such story begins with the patient showing up at Benjamin’s office at the age of 28, married, father of three children, a successful salesman, and asking for help because his recurrent transvestism was threatening his marriage.

Type III transvestite, you might think? Benjamin implies that was his initial diagnosis. But as more evidence came to light his diagnosis changed. That person described above is his example of a Type VI “high intensity” transsexual. They don’t get any more transsexual in Benjamin’s book.

If an expert like Benjamin could err so dramatically in diagnosing a patient, why do others seem so certain they can grab a few facts about a person – like marital status, age, and crossdressing history – and make a slam-dunk, unchangeable diagnosis every time?

Benjamin’s work was all about helping people. He found transsexuals a miserably unhappy and tragically underserved segment of the population. He didn’t look for someone else to blame. He rolled up his sleeves and made fixing this problem his life’s work. Those who use that work as a basis for belittling, mocking, and abusing others could not be more divorced from the example of Harry Benjamin himself, and do his legacy no favors.


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Just a quick link to share today. It’s not a new article. But I’ve been returning to it recently as a resource for countering some of the usual “transsexuals are unnatural” arguments, and I thought others might find it helpful for the same purpose.

It’s from The Organisation Intersex International (OII) Australia:

“I believe that transsexuals are intersexed individuals.”

Incidentally, the article’s position regarding the proper role of science in addressing these questions is one I strongly share. How come so many people who want to use “nature” to refute our existence seem so resistant to actually examining the natural evidence?

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An interesting story emerged this week about a figure of some notoriety within the trans world. It involves a certain J. Michael Bailey of Northwestern University. This time the dust-up doesn’t have to do with anything trans related but… well let’s just examine the story.

Evanston, Ill. – More than 100 Northwestern students watched as a naked woman was penetrated by a sex toy wielded by her boyfriend during an after-class session of the school’s popular “Human Sexuality” class.

The demo, which was optional, was part of the popular class taught by Prof. John Michael Bailey, the Sun-Times is reporting. More than 600 students take the class, which the course description says “will treat human sexuality as a subject for scientific inquiry.”

For some reason the general community is a bit upset with the good professor for staging something that sounds indistinguishable from pornography as part of a class demonstration.

But, as has been the case with Bailey in the past, this is not simply a matter of town and gown disagreement. Other academics also seem to question the scholarship involved here.

Bill Yarber, a researcher at Indiana University’s Kinsey Institute and author of the widely used textbook “Human Sexuality: Diversity in Contemporary America,” said he’s never heard of a naked woman being brought to orgasm in front of a class of students.

“They way you present it there is very unconventional,” he said. “There’s certain boundaries of things, I think, that are acceptable and that would certainly be pushing that.”

There’s more at the link, but you get the general picture. For nebulous reasons Bailey insists are properly scholarly, but other scholars can’t seem to grasp, he staged a live demonstration of something one usually  finds on internet pornography for his students. And then, when asked to explain the academic merit of this exercise…

Bailey could not be reached for comment.

Of course he couldn’t. The demands of science have surely called upon him urgently to explore the role of  Cinemax in nighttime erections, or to return to his research upon alternative modalities of picking up hookers in bars (“Hey baby, how about you come back to my place and we make some sweet, sweet science?”).

Those of us in the trans world who have had reason to sample Bailey’s “scholarship” in the past can only chuckle about this. You mean it’s possible this guy is a wee bit more sex-obsessed than scholarly? Who could have known? Oh… right.

I’d just like to submit this latest incident into the popular record. The man who attempted to popularize the notion that all transsexualism could all be explained by two flavors of erotic compulsion may have been projecting just a bit.


Lynn Conway, who was instrumental in leading the charge against Bailey’s anti-trans “research” has tracked down several  more articles on this matter. Here’s a sample:

F***saw: Northwestern University Professor John Michael Bailey Demonstrates Sex Toy to Class

Chicago Tribune exclusive interview: “J. Michael Bailey talks with Tribune columnist Mary Schmich”

Daily Northwestern: “Updated: Northwestern copes with fallout, attention from sex toy demo – Schapiro announces investigations; ethics claim to be filed by fellow scholar”

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The New Scientist reports a potentially groundbreaking study for the early identification of transsexuals. The  new study, about to be published in the Journal of Psychiatric Research, identifies a new method for identifying transsexuals before puberty and before hormone treatment by a newly discovered brain scan technique.

Antonio Guillamon‘s team at the National University of Distance Education in Madrid, Spain, think they have found a better way to spot a transsexual brain. In a study due to be published next month, the team ran MRI scans on the brains of 18 female-to-male transsexual people who’d had no treatment and compared them with those of 24 males and 19 females.

They found significant differences between male and female brains in four regions of white matter – and the female-to-male transsexual people had white matter in these regions that resembled a male brain (Journal of Psychiatric Research, DOI: 10.1016/j.jpsychires.2010.05.006). “It’s the first time it has been shown that the brains of female-to-male transsexual people are masculinised,” Guillamon says.

While it’s far too early to blow this out of proportion, the potential clinical implications are significant.

If the new technique is verified the identification of transsexualism would no longer need to remain solely in the variable hands of psychologists, who currently take from months to years to arrive at such diagnoses, and even then allow great latitude for their own individual interpretations. Quicker diagnosis means quicker access to treatment which means much greater overall health – mental and physical – for affected patients.

What’s more this study may prove the tip of the iceberg, allowing clinical identification of a host of related (or perhaps even unrelated) conditions. However it wouldn’t be wise to see this as a panacea, as the lead researcher notes:

Guillamon thinks such scans may not help in all cases. “Research has shown that white matter matures during the first 20 to 30 years of life,” he says. “People may experience early or late onset of transsexuality and we don’t know what causes this difference.”

In other words don’t look at this as a “catch all,” or “litmus test,” but rather one more tool by which science is building toward better understanding and treatment of this previously mysterious condition. Even if some of us (I’m looking at myself here) are pretty excited by the potential of this particular tool.

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The Science of Sexuality Explained

I’ve been so caught up crafting my own lengthy posts lately that I neglected to point out that Dr. Veronica Drantz recently posted video of her excellent presentation “Myth and Science of Sexuality – Disordered or Just Different.

Here is what the presentation is about, in Drantz words:


This video and the slideshow “Myth and Science of Sexuality – Disordered or Just Different?” of my presentation to the Ethical Humanist Society of Chicago on October 10, 2010,  explain the development of diverse sexualities (as natural variations of the organization-activation mechanism), and show that LGBTI peoples suffer persecution due to a socio-cultural disorder resulting from the erroneous “gender binary” concept.

I’ve linked to the slide show alone previously, but it really is MUCH better when you can listen to the presentation along with it.

Dr. Drantz does a phenomenal job covering a VAST amount of scientific information in a comparatively short span of time. But the nice thing about posting the slides and video is that it allows people who may feel overwhelmed absorbing so much all at once to go back and revisit the material at their own pace.

Regardless of your interest in trans issues, the science here is fascinating. I super-extra recommend watching the whole thing.

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Boy Genes

A new development in genetic research has uncovered yet another mechanism for male sexual differentiation without a Y chromosome.

Adelaide researchers have discovered a way of creating a male mouse without a Y chromosome by activating a single gene, called SOX3, in the developing fetus. SOX3 is known to be important for brain development but has not previously been shown to be capable of triggering the male pathway. …

Associate Professor Thomas and his colleagues have generated male mice with two X chromosomes by artificially activating the SOX3 gene in the developing gonads.

“These XX male ‘sex reversed’ mice are completely male in appearance, reproductive structures and behavior, but are sterile due to an inability to produce sperm,” he says.

In the popular mind, “science” says chromosomes define your sex. But ongoing research in molecular genetics is increasingly showing this to be a crude and oversimplified version of the truth. But when the facts consistently run against popular beliefs, eventually those beliefs are destined to change.

And lest we doubt that this research says something about the mouse’s bipedal, house-ape cousins, the researchers note…

Further collaborative research with Professor Andrew Sinclair at the Murdoch Children’s Research Institute in Melbourne and Professor Eric Vilain at UCLA (University of California Los Angeles) has also shown that changes in the human SOX3 gene are present in some individuals who are XX males.

“From a genetic perspective, cases of XX male sex reversal are particularly intriguing and are poorly understood,” Associate Professor Thomas says.

“This discovery provides new insight into the genetic causes of disorders of sexual development, which are relatively common in the community.

“For the future, this discovery will impact on the molecular diagnosis of these disorders and, ultimately, help us to develop therapies or technologies to improve clinical outcomes,” he says.

While some religious and social conservatives urge resistance to abandoning the chromosomal  XX = girl, XY = boy formulation, science marches on.

The march of scientific progress doesn’t always leave our pre-conceptions happily intact. Yet it can leave us happier still if we’re willing to show humility toward the facts.

There are more things in heaven and earth, Horatio,
Than are dreamt of in your philosophy.
Hamlet Act 1, scene 5, 159–167

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Note: This post is the continuation of a series regarding the current scientific understanding of transsexualism. It is intentionally light on scientific jargon and footnotes (though I can’t avoid them all), as it is an attempt at a narrative summary of complex underlying material. Some references are provided at the end, but none of these concepts are derived from a single source.

I left of the “Fact Not Opinions” series many months ago, so it probably makes some sense to summarize the series so far before proceeding.

The Story So Far

As the first post indicated, this series was motivated by my desire to get beyond the “X mind trapped in a Y body” analogy regarding transsexuals. After all the brain is a part of the body. If we mean “brain” when we say “mind,” then the truth we seek doesn’t lie in sharp rhetoric or forceful opinions, but rather in physical, empirical facts. Further, if these facts indicate that our bodies (especially our brains) do not match the gender we have been assigned, then our reality as transsexual beings cannot be a matter of opinion, nor can it be a matter of mental pathology. It must be a matter of fact.

The second post in the series reviewed the history of the psychiatric / psychological attempts to “cure” transsexuals by making their minds conform to their external bodies. A century of evidence strongly backs the conclusion that this approach doesn’t work. However when the alternative approach was finally attempted – using surgical reconstruction to make the bodies match the minds – it was met with success by all the relevant psychiatric measures. The psychologists still couldn’t explain why the one approach failed so conclusively, while the other approach succeeded. But evidence gradually overwhelmed disbelief, so that the “make the body match the mind” approach became the standard psychological treatment for a properly diagnosed transsexual.

The third post in the series began to explore the biological nature of gender formation. It reviewed the “nature versus nurture” controversy over the establishment of human gender identity. The two main views were represented by John Money, who believed that human babies are undifferentiated in terms of gender until many months after birth, and Milton Diamond, who believed that humans had their gender established via the Organization-Activation mechanism beginning in utero. The “John/Joan” case seemed to prove Money’s contention, while undermining any biological cause for transsexuality. However later followup studies exposed “John/Joan” as a fraud, discrediting Money’s contentions while simultaneously indicating that human gender conforms to the organization-activation theory, as Diamond predicted.

So now it’s time to get into organization-activation itself, and attempt to apply its mechanisms to understanding human sexual differentiation. But before we can do that we need to understand how organization-activation theory fits into the overall process of human sexual differentiation. And in order to do that, a primer on the topic is in order.

Beyond Chromosomes

Just about every educated person is taught that human sexual differentiation is a matter of chromosomes. If the chromosomes show an XY pattern, that indicates a male. If the chromosomes show an XX pattern that indicates a female. For the vast majority of humans this is certainly true.

But it can also be said that we know this is not true in every case. There are a number of known intersex conditions, ranging from people with rare chromosome patterns (e.g. XXY), to people born with with opposite physical anatomy than their chromosomes would indicate (i.e. XY girls, and XX boys), and this is only scratching the surface of medically known variations. In order to explain the alternative development patterns leading to these non-standard outcomes it is necessary to understand more than simply chromosome patterns. It is necessary to understand how the chromosomes themselves do the work of sexual differentiation and how, sometimes, they may not follow the expected pattern of development.

In 1947, French endocrinologist Alfred Jost demonstrated that both XX and XY mammals would develop as females if the XY mammals were castrated in utero before sexual differentiation. The implication of this work was that female represented the “default” state of sexual development in mammals. In other words, in the absence of additional factors driving a fetus to develop as a male, we get a female. But what were these additional factors driving male development? Jost’s work suggested the driving force was not  chromosomes, but rather the presence of absence of the male gonad. But as all fetuses begin without sexual differentiation – including their gonads – this begged the question. How and why was the gonad differentiated in the first place, and why was there such an overwhelming correlation with the presence of a Y chromosome?

Genetic Differentiation

Studying the Y chromosome, scientists first linked the development of male testes to a single region of said chromosome (a region known as TDY, for Testes Determining Region). Subsequent research isolated testes development still further to a single gene known as SRY (for Sex-determining Region Y). Most of this was discovered by studying XX male individuals; living demonstrations of just how little Y chromosome material was needed to cause a fetus to develop as male (genetic material from a Y chromosome can pass to an X chromosome due to  abnormal recombination during male meiosis). It is now believed that the SRY gene is the sole trigger which sparks an otherwise female mammal to develop as a male.

To extend the analogy of the trigger a bit further, if SRY is a “trigger,” what does it “fire?” Being a gene, SRY is essentially a blueprint for manufacturing certain proteins. So when the SRY gene is “fired,” production of SRY proteins begins. But what do these SRY proteins do?

Here we start to hit against the edge of current scientific understanding. We know that SRY proteins bind to certain genes. We don’t know exactly which genes they bind to. It is suspected that bound SRY acts as a transcription factor, causing other genes to be expressed. It is not certain which gene or genes these might be (it isn’t even known if SRY binds to one gene or multiple). In addition to causing some genes to be expressed it has also been hypothesized that SRY may cause other genes to be repressed. The exact mechanisms underlying all of this remain unknown. What is known is that both the timing and the level of SRY expression are critical. If either of these factors is off, it can lead to the development of an XY female.

In summary, the SRY gene, properly timed and expressed, will lead a mammal to develop testes. Absence or under-performance of this gene will lead a mammal to develop ovaries. The main role of both of these organs is the secretion of specific kinds of hormones.

Hormonal Differentiation

The importance of testes or ovaries in early sexual differentiation is keyed upon the hormones they secrete. Unfortunately our understanding of this at present is very one-sided.

Early research into sexual differentiation was based in the belief that the development of a male required biological processes triggered by hormones, while the development of a female merely required the absence of these hormones and processes. It is now known that this assumption was false. Both paths of development require distinct and equally complex biological processes triggered by the presence and/or absence of hormones. However there remain strong indications that one of the key roles of male hormones during fetal development is to counter certain “default” female development pathways. Nonetheless, our knowledge of hormones in male development is greater than the female equivalent at the present.

Hormones are often called the body’s  “chemical messengers.” They work by penetrating target cells and binding to specific receptors. Once a hormone finds its proper receptor it causes certain genes to be expressed, which in turn cause certain proteins to be created, which in turn trigger still further development. If a hormone cannot bind to its target receptor, it can have no effect. (So far we have followed a well researched path involving the development of hormone secreting glands. Keep in mind that the far less understood processes underlying the development of cellular hormone receptors are equally important to sexual differentiation.)

In mammalian sexual differentiation hormones first play an active role in the development of distinct sets of anatomical structures.

Anatomical Differentiation

A clear example of male hormones inhibiting an otherwise female direction of development involves MIS, the müllerian inhibiting substance (sometimes called AMH, or anti-müllerian hormone). Regardless of eventual sex, all mammals possess the building blocks for two sets of internal reproductive structures known as the Müllerian and Wolffian ducts. The Müllerian duct is capable of developing into female internal structures (fallopian tubes, uterus, cervix, etc.). The Wolffian duct is capable of developing into male internal structures (epididymis, vas deferens, seminal vesicle, etc.).  Once the male testes develop they begin to secrete the MIS hormone, which has the dual purpose of developing the cells which produce testosterone and causing the Müllerian duct to degenerate. In the absence of this hormone, the Wolffian duct will degenerate and the Müllerian duct will develop. This is one of many examples illustrating that ultimately it is the presence or absence of hormones driving the sexual differentiation of a bi-potential anatomy.

The continuing development of the male testes leads to the development of two additional key hormones, testosterone and dihydrotestosterone, or DHT. Testosterone triggers Wolffian duct development , and serves as a building block for the creation of DHT. DHT is responsible for the development of male internal and external anatomical structures. Further,  DHT is known to have a role in organizing (per organization-activation theory) sexual differentiation in the brain (more about that in a moment).

External genitalia are determined by the effect of DHT around the 9th week of fetal development. At this time the external genitalia consist of a bi-potential genital ridge rich in DHT receptors. In the presence of sufficient quantities of DHT, the genital ridge will develop into a scrotum and penis. In the absence of DHT (or if this is lacking in sufficient quantity), the genital ridge will develop into a labia and clitoris.

All the physiological sexual differentiation examined to this point is capable of speaking to the vast majority of currently known intersex conditions. But it still cannot explain transsexualism. In order to do this we need to take one further step.


We are now at the point of mammalian sexual differentiation where organization-activation theory comes into play. A quick definition:

The organization-activation theory posits that the nervous system of a developing fetus responds to prenatal androgens so that, at a postnatal time, it will determine how sexual behavior is manifest.

from the Abstract: Clinical implications of the organizational and activational effects of hormones. Diamond M., Horm Behav. 2009 May;55(5):621-32.

Lest this simple definition is unclear, I’d like to restate it. Diamond is suggesting that sexual differentiation in the brains of mammals – including humans – is accounted for by prenatal male hormones, exactly the same way they account for the development of earlier anatomical structures. This prenatal brain differentiation accounts for later differentiation in behavior between males and females.

This notion, if true, is directly applicable to exploring a biological basis for transsexualism. We have already established that if an XY individual lacks sufficient male hormones, that individual will develop the anatomy of a female. Conversely, if an XX individual begins producing sufficient male hormones, that individual will develop the anatomy of a male. Interruptions or variations in expected hormones cause interruptions of variations in expected sexual differentiation – causing total sexual reversal in extreme cases. Organization-activation suggests that this very same principle is at work in the sexual differentiation of an area of mammalian biology (i.e. the brain) linked to identity and behavior.

Or, in Diamond’s own words:

I believe that transsexuals are intersexed in their brains as others are or might be more obviously so in their gonads, genitals, hormonal character, receptor, enzymatic or chromosomal constitution. And it is this brain intersexuality that biases the person to assert his or her gender identity.

If Diamond is correct it should be possible to find sexually differentiated structures within the brain within which transsexuals match their stated gender identity while at odds with their chromosomes or external anatomy. But that’s getting ahead of ourselves. We’ll save that for another post.

In Summary

For those who stuck with the post this far, let’s sum up. Here is what we know about the process of sexual differentiation in mammals (including humans):

  1. Chromosomes carry sexually differentiating genes (chromosomal differentiation).
  2. These genes, once expressed, (genetic differentiation) …
  3. cause the development of hormone secreting organs . These distinct sets of hormones (hormonal differentiation)…
  4. … result first in the development of sexually differentiating anatomical structures (anatomical differentiation)…
  5. and later the same hormones play a role in sexual differentiation of the brain (organization-activation).

Further Reading:

Sex Determination and Gonadal Development in Mammals
Beginner’s guide to genetics: Sex and genetics
Chromosomal Sex Determination in Mammals

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