If you look at the biology of how sexual development occurs, both intersex and transgender have the same underlying cause: abnormal hormone levels during part (or all) of your prenatal development (or, with AIS, normal hormone levels but an inability to respond to those hormones).

There's this deeply ingrained belief amongst the general populace (and even most doctors it seems), that your sex is determined by whether you have a Y chromosome or not. However, that's not how it actually works at all. All the Y chromosome does is, during a critical window from about 6 to 8 weeks after conception, cause your undifferentiated gonads to turn into testicles. Once your testicles form, they promptly start churning out testosterone, and the testosterone (and DHT, a hormone that's made from testosterone) causes you to develop as male. It's the testicular hormones that cause you to develop as male though and not the Y chromosome, and without those hormones (or, in AIS, if the body can't respond to male hormones), then you develop as female instead. This is demonstrated very well by the condition Complete Androgen Insensitivity Syndrome, in which genetically male people develop as female.



A similar thing happens in Swyer's syndrome, in which the testicles fail to develop for whatever reason, in otherwise genetically male people:



In both cases, the male hormones testosterone and DHT completely fail to act throughout prenatal development. The result is you end up with a person who is infertile, but otherwise to all intents and purposes a woman, despite having a Y chromosome and being genetically male. This shows that the sex you develop as is entirely determined by what hormones are present during the time your prenatal development is taking place, not by whether you have a Y chromosome or not.

If anything happens to disrupt your hormone production during that critical time, it's easy to end up in a situation where some of your development has occurred as male and some as female, and that's how both intersex and transgender can arise. With intersex, the hormone disruption has occurred during the first trimester (which is the critical time for genital development), whereas with transgender, it's occurred during the second and/or third trimester (by which time genital development has finished, and the main thing still ongoing is brain development). There's a fair bit of overlap between the two though. For instance, most of the XXY people I've chatted to are quite genderfluid, and Caroline Cossey is one well known example of an (XXXY in her case) intersex person who's also transgender. A lot of transgender people who were exposed to DES also have intersex-related genital abnormalities, so there's definitely an overlap between the two in that situation as well. There's also plenty of animal research showing that exposure to external hormones early in prenatal development affects genital development, whereas later in the pregnancy it causes cross-sexed brain development.

I think probably the main reason why there's so much mystique about the whole thing, is because doctors and the pharma industry don't want to admit that most of us have ended up the way we are through their reckless use of hormones in pregnant woman!

WARNING: RANT AHEAD

Can we lay off with the conflation of "transgender" with "intersex"?

As Cindy has already pointed out (and she is AFAIK more of an expert than any of the rest of us), "intersex" refers to a particular well-defined set (category?) of conditions, and what we think of as "transgender-ness" isn't one of them. To claim that being trangender is an intersex condition is rather like me claiming that, because I'm a "native" of "America" (i.e., born in North America), I am therefore a "Native American" even though AFAIK all of my ancestors came from Europe after 1492.  No.  It doesn't work like that, and claiming it did would be insulting and invalidating to actual Native Americans, who get saddled with enough dreck as it is for being NA.

(And, yes, some of us are both transgender and intersex.  Most of us here are not.)

But I have a second rant:

I'm tired of all the memes about what "caused" our transgender "condition."  People who are red-haired or a little on the short side or like red hot chili peppers don't feel the need to explain or excuse their "condition;" they get away with saying, "well, I guess that's just how I was made."

Well, I'm transgender, and that's just how I was made, and that's the end of it.  I don't know what "caused" it and I don't need to know -- I mean, what difference does it make whether it's genetics or hormones or my mother being kidnapped by space aliens?  It won't change who I am.

And who I am is just fine.  There's nothing wrong with me; it's the people who can't deal with it that have something wrong with them.

My being transgender is not a "condition" or a "disorder" or an "anomaly" or a "disability."  The only reason my being transgender is a problem at all is because all my life society has insisted that "something is wrong with you" and tried to beat it out of me.  Talking about being transgender as if it were a disorder implies that it's something to be "cured" or "prevented," when it is actually a normal variation that's been around forever and IMHO, like genetic diversity (or green vegetables), actually makes society healthier.  (Cue sound bites of right-wing politicians calling green vegetables a "bigger threat to humanity than nuclear war.")  I don't need to be "cured" of anything except the damage inflicted on me in childhood by the supposedly well-meaning adults around me beating me into a shape that fits the Boy Standard.  (The original Boy Standard is, of course, kept in a vault in Paris, like the standard meter or the standard gram.)

Trying to explain or excuse our being transgender is just letting the transphobes choose how we're allowed to discuss things.  To that I say: pbbbt!

Quote from: Asche on November 21, 2015, 06:07:12 AM
WARNING: RANT AHEAD

Can we lay off with the conflation of "transgender" with "intersex"?

As Cindy has already pointed out (and she is AFAIK more of an expert than any of the rest of us), "intersex" refers to a particular well-defined set (category?) of conditions, and what we think of as "transgender-ness" isn't one of them. To claim that being trangender is an intersex condition is rather like me claiming that, because I'm a "native" of "America" (i.e., born in North America), I am therefore a "Native American" even though AFAIK all of my ancestors came from Europe after 1492.  No.  It doesn't work like that, and claiming it did would be insulting and invalidating to actual Native Americans, who get saddled with enough dreck as it is for being NA.

(And, yes, some of us are both transgender and intersex.  Most of us here are not.)

But I have a second rant:

I'm tired of all the memes about what "caused" our transgender "condition."  People who are red-haired or a little

[...]

Trying to explain or excuse our being transgender is just letting the transphobes choose how we're allowed to discuss things.  To that I say: pbbbt!

(cut for length)

I've gotta say that I agree with everything you said - I don't personally feel the need to justify being trans by also being somehow intersex, but I understand completely why people do so. It's difficult when other people see being transgender as a political choice, and therefore up for debate. If there is a genetic cause it's harder for us to be brushed off as kinks and freaks, and the general populace is generally aware of intersex. 'It's just how i was made' is easier to reject and justify discrimination. They can't claim that genetic conditions don't exist; you can't say that Deaf person is just not trying or that an albino is just looking for attention. If transgender doesn't have a biological cause, what is it? Is it a personal choice? It doesn't feel like one. It is a shame we have to ask that question though - but blaming ourselves for reacting to a hostile society by trying to simply medically explain us isn't really progress.

I don't like the idea of finding a 'gay gene' either - that just looks to me like a doorway for eugenics to make a comeback, same as if there was a 'transgender gene'. The only upside is that it would shut up people who consider sexuality and gender a lifestyle choice. In an ideal world transgender and intersex wouldn't be conflated because people would be as accepting of both but until society moves on they probably will continue to be. :/