Exactly, Hugh. All of the groundwork gets laid in utero, in particular during the 8th-16th week of pregnancy when the sex glands begin their descent from the base of the brain down to the pelvis. It is at this time that sexual hormone production begins in earnest and anything that disrupts that production or alters the "normal" ratio of testosterone to estrogen (females produce testosterone too, just the ratios are very different) can cause variations, particularly in the brain itself because the brain is more isolated from the rest of the body due to the brain-blood barrier.

For example, at the age of 38 I was diagnosed with a media-stinal germ cell tumor. This tumor appears to be the direct result of sex gland material that gets deposited in the chest (media-stinal) during the descent of the sex glands during the 8th-16th weeks of pregnancy. My oncologist, Dr. Robert Amato, one of the leading researchers in the world at that time on media-stinal germ cell tumors, said that in his data every single patient had mothers who were heavy smokers during pregnancy. This latent germ cell material then lays dormant in the chest until it randomly gets activated and becomes one of the fastest growing tumors in the cancer world.

When I began therapy with my therapist years later, I reached out to Dr. Amato, who was no longer at MD Anderson Cancer Center but over a Baylor and asked him if the mechanism that would cause tissue to break off and form a latent germ cell tumor would also cause disruptions in production of testosterone. His reply was "Absolutely!" And that it might take weeks to return to normal levels of hormonal production.

Though I cannot absolutely prove it, the data now strongly suggests that my own transgender nature, which I've had since very young is a direct result of this.


Also, there are XX males, who have what is known as de la Chapelle syndrome. It is caused by unequal crossing over between X and Y chromosomes during meiosis in the father, which results in the X chromosome containing the normally-male SRY gene. When this X combines with a normal X from the mother during fertilization, the result is an XX male.

This syndrome occurs in approximately four or five in 100,000 individuals, making it less common than Klinefelter syndrome.

According to research at the University of Oklahoma health science centers, most XX males are not stereotypically feminine and are typical boys and men although other reports suggest that facial hair growth is usually poor and libido is diminished, with notable exceptions.

So once again, genes themselves are not the determinants but only the blueprints and if those blueprints are implemented in a non-standard way, variations result.

Since we know that extremes of hormonal variations, such as de la Chapelle babies and AIS babies are possible, does it make sense to believe that less extreme variations might occur that explain being trans? Yes, that makes a lot of sense.

And we discover that DES babies (from the 1940s and 1950s when mothers were routinely administered DES during pregnancy which has since been banned precisely because it interferes with hormonal actions) have extremely high rates of being trans, being gay, and being intersex.

So all of the evidence begins to point towards hormonal variations as a root condition in being trans. And then the neurobiological research that I provided above shows that researchers now accept and began looking for proof of this in the brain and have found it in abundance.


Note that this does not discount the impact of "nurture" in this equation, but instead simply asserts that in the majority of cases a hormonal variation during pregnancy is likely what created the preconditions to being trans later in life. It would not surprise me at all to discover that this precondition is often coupled to other "nurture" factors but I would also wager money that in the majority of trans cases, the underlying brain structures are exactly as expected - for MtFs a female structured brain in a male body, and for FtMs a male structured brain in a female body.

Quote from: Edge on November 13, 2014, 09:50:05 AM
I guess it comes down to how one defines "gender." Personally, I reject the notion that gender is the same as gender roles, stereotypes, behaviour, clothes, etc. To me, gender is something much more abstract that we don't fully understand yet, but is a part of the bigger picture of who we are rather than something that controls who we are. If that makes sense. According to what information we have so far on gender (my definition anyway) and the brain (which, admittedly is currently far from complete, but that doesn't make the information we have learned any less), I would say that gender is determined by those brain structures, but those brain structures (and gender) do not determine patterns of behaviour that are illogically associated with gender.
I hope I made sense. I'm not meaning to argue. Just explaining as best I can how I see it. I should also point out that I'm a fan of science, a biology student, and a brain fanboy whose long term plans involve becoming a research neuroscientist because I think brains are the most fascinating things ever.

I actually kind of agree with you, I believe there is a structural element involved in the construction of ones gender identity, I just vehemently believe it has no effect on behaviour, because neurosexism really sucks. And I also believe that constructed gender roles and norms of gendered behaviour can and do have a profound effect on an individuals gender identity, mainly due to the synaptic rewriting of neuroplasticity.

I talk about this subconscious sense of self a lot and it is important, especially if it clashes with the physical reality of someone's body. This isn't something that is taught or learnt, I believe it to be innate and probably structural in nature, i.e. having a brain wired to expect testosterone but instead having an endocrine system flooded with estrogen. It would cause an innate physical wrongness with your body, which is what I believe dysphoria to be, a mis-match between what the brain expects the body to be and how it actually is. But it's not the totality of gender identity, merely a part of it. This is what I mean why I say that we construct our gender identity from a variety if cues, both learned and innate, conscious and subconscious. Kind of similar to the way we construct our full identity.

Mostly this is speculation on my part, I've thrown the idea at a few friends and it fits with their experiences as well as mine, it's most likely flawed, but at this moment in time it works for my understanding of being trans because it neatly torpedoes what I see as flawed, biologically essentialist explanations of being trans.

Quote from: Dread_Faery on November 13, 2014, 07:10:01 AMThe truth is there are structural differences between male and female brains, but their so slight as to have not tangible effect on behaviour.

They DO have a tangible effect on behaviour because numerous studies have linked structural brain differences with transsexualism. This plays out in a prolonged experience of gender dysphoria for the individual that cis people do not experience and can not comprehend. Is hardly reasonable to consider this experience 'not tangible'.

In my case, I would exclude any possibility of drug effects in the womb, as my country was very poor and most people probably could not afford to purchase those pills when I was born.

I wished to be a woman when I was 4 years old, trying to wear women's clothes. I am sure I am not an intersex.

During my puberty, my body and face became feminized in the modern standard (slim legs/waist, relatively big pelvis, laughing like a woman, slender body figure, frequent crying, and etc), inciting all kinds of comment from a little girl to old men/women that I look like a girl. However, I was biologically male (XY) anyway. After my 20s, I could live as a typical male, a successful one.

It was my later 30s that I realized my transsexualism clearly. Looking at the mirror, I thought I will look better with women's clothes. While exercising outdoors, I noticed that some men watch my legs in summer. I shaved my legs and started to grow my hair. It went on and on, despite several pauses. I have never been on HRT, although I once unsuccessfully tried it. Nowadays I wear skirt, fishnet and heels in my work place. Most people seem to accept it, not owing to my pass-ability or beauty at all, but to my outstanding performance as a dad, a husband and a colleague.

I am a kind of Narcissist. I see a woman in the mirror when I am naked. My transsexualism in my brain seems to interact with my physical appearance (both body and face) through my eyes. It becomes stronger when I wear some makeup.

I guess there are a few transgender people like me. Both of my mind and physical body are feminine to some extent.

I believe the womb hypothesis, as my brother, my close male relatives, or my sons have never shown any symptom of transsexualism. The body figure of my brother is not so much feminine. The standard of femininity is certainly socially-constructive at some extent, but I guess there are some universal or ubiquitous commonness.

barbie~~

Oh. One thing was forgotten. My unique difference from my male relatives was that I was malnutritioned when I was 0 to 1 years old. My mother did not produce enough milk. They tried powdered milk unsuccessfully. And they tried some oriental medicine, causing me to suffer from diarrhea for 6 months thereafter. I became extremely lean and I guess this explains why my body and facial figure is so much feminine in the modern standard (underweight and a thin waist is what women wanted now all around the world). Fortunately, I am now very healthy compared to my contemporary, partially owing to my early malnutrition. Some studies also show that eating less is better for health and longevity. Most women envy me for my slim legs and waist. I guess the condition during infancy is also critical in causing transsexualism.

barbie~~

Quote from: Dread_Faery on November 15, 2014, 08:09:23 PM
I actually kind of agree with you, I believe there is a structural element involved in the construction of ones gender identity, I just vehemently believe it has no effect on behaviour, because neurosexism really sucks. And I also believe that constructed gender roles and norms of gendered behaviour can and do have a profound effect on an individuals gender identity, mainly due to the synaptic rewriting of neuroplasticity.

I talk about this subconscious sense of self a lot and it is important, especially if it clashes with the physical reality of someone's body. This isn't something that is taught or learnt, I believe it to be innate and probably structural in nature, i.e. having a brain wired to expect testosterone but instead having an endocrine system flooded with estrogen. It would cause an innate physical wrongness with your body, which is what I believe dysphoria to be, a mis-match between what the brain expects the body to be and how it actually is. But it's not the totality of gender identity, merely a part of it. This is what I mean why I say that we construct our gender identity from a variety if cues, both learned and innate, conscious and subconscious. Kind of similar to the way we construct our full identity.

Mostly this is speculation on my part, I've thrown the idea at a few friends and it fits with their experiences as well as mine, it's most likely flawed, but at this moment in time it works for my understanding of being trans because it neatly torpedoes what I see as flawed, biologically essentialist explanations of being trans.

Yes, that is essentially what modern neurobiological research is saying. There are underlying biological structures that provide what you called "cues" and then there are external "nurture" factors that are socially defined by each culture that layer on top of these cues. And our dysphoria comes from the internal cues being completely at odds with the external social definitions that are often thrown at us because of a cursory examination of our genitals when we are born.

Quote from: LizMarie on November 16, 2014, 02:23:57 PM
And our dysphoria comes from the internal cues being completely at odds with the external social definitions that are often thrown at us because of a cursory examination of our genitals when we are born.

Maybe yours is, but mine is from the internal cues of what my body is supposed to look like being completely at odds with the external reality of what my body does look like. For me, it's mostly physical, not social.
Again, not meaning to argue. Just pointing out that dysphoria is different for different people.

My understanding is that it's not gender identity that might develop in the womb but that your brain might diverge there. One theory is that there are several "dumps" of hormones early on. The first one develops physical traits but there is a later one that develops the brain.

For instance, like this: http://www.majickalproductions.biz/bekasite/resouces/In-Womb%20Development.htm

--Jay

Quote from: aleon515 on November 17, 2014, 02:06:09 PM
My understanding is that it's not gender identity that might develop in the womb but that your brain might diverge there. One theory is that there are several "dumps" of hormones early on. The first one develops physical traits but there is a later one that develops the brain.

For instance, like this: http://www.majickalproductions.biz/bekasite/resouces/In-Womb%20Development.htm

--Jay

The page you've linked to is mostly right,  however it's a lot simpler than they make out. By default, your prenatal development occurs as female, whereas if there's androgenic hormones present, it occurs as male.

In rodents, testosterone is converted into estradiol and it's the estradiol acting on estrogen receptors in the brain that drives brain masculinization, however that's not what occurs in people (or other primates it seems). In humans, all male development seems to be driven solely through the action of androgenic hormones on androgen receptors. This is shown by the fact that CAIS women seem to invariably be psychologically female as well as female in appearance, and also in the research on Rhesus monkeys. There, testosterone and DHT were equally effective at driving male brain development in the genetically female monkeys they were experimenting on, even though DHT doesn't aromatise and so doesn't cause any estradiol to be produced.

The critical period for male genital development starts about 7 weeks after conception and has finished by the end of week 12. A female fetus exposed to androgenic hormones during that time is likely to end up with intersexed or male genitals; a male fetus whose testosterone production isn't up to par during that critical period is likely to end up with intersexed or female genitals. If your hormones are normal during that critical period but then get messed up at some later stage of the pregnancy, there won't be much effect on your genitals or reproductive organs (genetic females could end up with an enlarged clitoris; genetic males, a penis shorter than it otherwise would have been and undescended testicles, or abnormalities associated with testicular descent, such as inguinal hernias). Basically your genitals and physical appearance will be that of your genetic sex though.

However, there's a critical period for sexually dimorphic brain development too, which, in Rhesus monkeys, is the entire second half of the pregnancy. What limited evidence there is seems to point to the same thing applying to humans (although in our case, normally developed male babies continue to produce testosterone for several months after birth,  which suggests that some of our sexually dimorphic brain development might take place after birth too).

Even if some things associated with having a male brain develop after birth, whatever it is that drives gender identity later in life seems to already be in place by the time you're born, since in the David Reimer case and in the male cloacal exstropy patients who were reassigned to female, they were castrated shortly after birth as part of the reassignment surgery, but nonetheless retained a male gender identity.

So, we know that both your physical sex and your "brain sex" depend on what hormones were present during your prenatal development, not on whether you have a Y chromosome or not. The details of what goes on (particularly as far as brain development is concerned) aren't at all well understood though.

Quote from: Edge on November 17, 2014, 08:35:41 AM
Maybe yours is, but mine is from the internal cues of what my body is supposed to look like being completely at odds with the external reality of what my body does look like. For me, it's mostly physical, not social.
Again, not meaning to argue. Just pointing out that dysphoria is different for different people.

Understood! And I wasn't clear as to my meaning. For me, my brain has screamed "female" all my life and my body went another direction. Because of my body going that direction, everyone treated me as male when internally I was not. And I too had severe body dysphoria, to the point of nearly mutilating my genitals as a teenager. The only reason the body dysphoria is under control now is that intellectually I know that I need that material for GCS later, and that I am actively moving towards GCS eventually, even if it is slower than I would prefer.

But also, as you note, how these factors manifest from person to person varies greatly.

Zinnia Jones, a well known trans blogger and activist, even wrote about how gender dysphoria can manifest in non-obvious ways.

"That was dysphoria?" 8 signs and symptoms of indirect gender dysphoria