April 23, 2010

Genes, hormones, sex and gender identity

What does modern biology tell us about sex and gender? I have done some reading for you.

When working on my blog posts on Gilmartin's love shy male lesbians, I realized that I have never really tried to get to the bottom of what modern biology has to say about sex and gender.

In my post on What brain science says about M2F transsexuals I presented some recent research on various nuclei (brain sectors) that may or may not govern sexual orientation and gender identification.

Given that I am planning to present Gilmartin's explanation for the existence of male lesbians in my next post, I believe it could be useful to have a popular summary of what contemporary science says about genes, hormones, sex and gender.

And as always: These are theories being constantly revised by the scientific community. Do not read this as the final word on the biological basis for sex and gender.

The life of the fetus

There are several variables that influence the sexual orientation and the personality of the fetus. We all know about the sex chromosomes (XX for women and XY for men). What many do not know is that only a small number of sex differences are directly caused by the sex chromosomes.

The majority of sex differences are thought to be not sex linked, but sex limited. They are caused by genes that are present in both sexes. This means that men have most of the sex and gender relevant genes women have (and visa versa). Potentially an XY "male" can develop practically all of the traits that define a biological woman.

These sex difference genes can be dichotomous (which is a fancy word for an on/off switch) or they can be continuous, which large variation between two extremes. The combination of all the sex limited genes forms the biological basis of the sex identifying aspects of a personality.

I like to picture this as a huge audio mixing table of the kind they use to produce records. There are on and off switches to open or close channels and tracks. There are sliders to adjust volume, frequency, dynamics, and panoramic position. And there a buttons for special filters and effects. One slider may also be the slave of another. This means that the adjustment of one slider will make another one move as well.

In a similar (but not identical) way nature uses genes, hormones and hormone receptors to produce the unique "mix" of a human being. Some of us come out as R&B, others as hard rock and some as melancholy blues.

The modern sex narrative

The traditional narrative these days is that the male Y chromosome has a gene complex called TDF (the Testes Determining Factor). The TDF has a gene called SRY (Sex Determining Region of the Y-chromosome. Duh!).

The TDF acts as a trigger that turns on genes that are found on the non-sex specific chromosomes, the ones that controls the development of the male testes.

All embryos -- male or female -- have the genes that encode the blueprint for both male testes and female ovaries. If the TDF is not there, the genes that encode the blueprint for the ovaries will turn on instead. You can say that the female bodyplan is the default. We are all girls before the TDF swings into action, according to this story.

Roughgarden's more complex narrative

Joan Roughgarden (who I presented in my Sex, Gender, Nature series) argues that this narrative is too simple, and that the SRY can only partly influence gendered presentation.

She (and many other biologists) argue that the sex of an embryo is evident even before the gonads differentiate into ovaries or testes. The gonads can develop at least partially into testes on their own, even without the SRY.

There are other mammals and vertebra that do not have the SRY, but that develop testes all the same. Moreover, the SRY is changing fast from an evolutionary perspective, and varies a lot within specific species, homo sapiens included. What nature considers "masculine" varies.

But she also agrees that the SRY is important. And truth to be told, also the "traditionalists" agree that the SRY is not alone in switching on the process that gives men testes.

Making testes

Roughgarden gives the following explanation. (Evolution's Rainbow p. 199. Do not get caught up in the names and abbreviations. This is only to give you an impression of how damned complex these processes are):

1. The gene WTI prepares the genital ridge and adjacent kidney area. Then the genes SF-I and WTI together urge SOX9 to make a testis. SOX9 is found on a non-sex chromosome. It is not part of the male Y-chromosome.

2. In girls the "anti-male" gene DAX-I intervenes, preventing SF-I and WTI from activating SOX9, so an ovary forms instead. This is one of the reasons Roughgarden is skeptical towards the idea that the default body plan is female. In this case you may say that default is male, and DAX-I must be turned on to make a girl.

3. In males, SRY inhibits DAX-I, permitting SF-I plus WTI to activate SOX9, which in turn produces a testis.

In Roughgarden's words:

"The SRY stops a gene, DAX-I, which itself was stopping testis development according to SOX9's recipe. Wow, not simple. Notice that SRY and DAX-I don't contribute materially to the recipe for making a testis. They are at the conference table just to argue, like genetic lawyers." (p. 200)

Note that even if SRY manages to get the body to produce a testis, which again produces testosterone, the battle for male-hood has not been won:

"The genetic bureaucracy may partially implement the legislation by ensuring that testosterone has only little effect, or it may fail to implement the legislation at all, as in the case of complete androgen insensitivity." (p. 201)

An XY individual with complete androgen insensitivity will appear as fully female, as the lack of testosterone receptors means that process of masculinisation never gets going.

A Y does not a man make

Here's a comment made by Eric Vilain, an assistant professor of Human Genetics at UCLA:

"We know that, there are a number of babies born who are male-they have two testes and penis - and yet they do not have a Y chromosome. We started to decipher the molecular mechanisms that lead to this situation and we now know that there [are] a few other genes that can sometimes mimic the action of the genes in the Y chromosome. So the Y chromosome is not this single force that pushes the whole male sex determination pathway."

Vilain also makes the following comment that supports Roughgarden's argument:

"The idea is in instead of having a simplistic mechanism by which you have pro-male genes going all the way to make a male, in fact there is a solid balance between pro-male genes and anti-male genes and if there is a little too much of anti-male genes, there may be a female born and if there is a little too much of pro-male genes then there will be a male born. We [are] entering this new era in molecular biology of sex determination where it's a more subtle dosage of genes, some pro-males, some pro-females, some anti-males, some anti-females that all interplay with each other rather than a simple linear pathway of genes going one after the other which makes it very fascinating but very complicated to study."


Ok, back to the traditional narrative (the one were we all start out as female):

The fetal gonads (testes or ovaries) produce hormones, primarily testosterone in the testes and estrogen in the ovaries. The testes also produce a hormone called MIS (Mullerian Inhibiting Substance or Anti-Müllerian hormone). The MIS causes the regression of internal female genitalia (defeminization). The testosterone leads to development of male genitalia (masculinization). No specific hormone is needed to develop the female genitalia. They are the default.

So a man becomes a man through two processes: a process that removes the female genitalia, and -- presumably -- also reduces some feminine traits (defeminization), and one process that generates male genitalia and encourages male traits (masculinization).

The hormonal balance produced by the testes or the ovaries is not dichotomous (an on/off variable). The amount of hormones will vary from fetus to fetus, and that variation will influence the development of the fetal brain and the "sex mix" of that individual. It seems the hypothalamus is organized differently in males and females.

Hypothalamus etc.

The hypothalamus controls the pituitary gland, which again controls hormone production in other glands. Because of this fetal brain development may also influence the future production of sex hormones in the body, and through this also future sex differences.

But that is not all: The hypothalamus also governs various natural drives, including hunger, thirst and sex drives. Different aspects of the sex drive (like sexual orientation and sex drive intensity) are regulated by different nuclei (sectors) of the hypothalamus. Many researcher believes that the basis for gender identity is also found here.

Other parts of the brain may also respond to sex hormones, and some researchers believe these are relevant to the development of brain lateralety, visuospatial learning, spatial memory, aggression, motor activity, exploratory activity etc, which all are associated with typically male and female abilities according to this line of research.


Studies of birds and rats show that their gender behavior may be changed by giving them hormones or by removing certain parts of their brain.


"When pregnant female rats are stressed in the laboratory by shining bright lights on them all day long, the male embryos in the litter produce less testosterone during their fetal period. They wind up with smaller clusters of nerve cells in the preoptic area and fewer nerve cells in the spinal cord for control of the penile muscle." (p. 225)

When testosterone drives feminization fantasies

It is important to notice that there are two sides to the effect of hormones: hormone production and hormone receptors. It does not matter if the hormone production is normal, if the receptors are lacking or react differently. This adds another dimension to the complex interplay between genes, hormones and sexual development.

The psychologist Anne Vitale has speculated on the role of testosterone as a driver for feminization urges among some M2F transgender. This may sound completely counter intuitive, as testosterone is the hormone leading to a masculinization of the fetus and the grown man.

She argues that her observations of her own patients lead her to believe that a subset of genetic males appear to respond to testosterone in a manner that evokes an overwhelming desire to express feelings of femininity.

She notes that male patients with gender dysphoria who get estrogen often find that their anxiety and their desire to cross-dress subsiding. On the other hand, F2M transgendered find that an increased intake of testosterone makes them feel better.

Vitale says:

"It is beyond dispute that there are both androgen and estrogen receptors in the brain. Genetic males normally have more active androgen receptors than women and women have more active estrogen receptors then men. That this 'normal' distribution of estrogen and androgen receptor cells can be different in some individuals appears to be a possibility. It therefore follows that androgenic and estrogenic compounds will result in a modified-to-counter expected behavior in affected individuals. For reasons beyond the scope of this Note and as counterintuitive as it may seem, it can only be assumed that testosterone plays a crucial role in forcing certain male individuals to crossdress and experience femininity to the maximum degree possibly."

To add my own 2 cents: If testosterone plays a role in sexual arousal (and it most likely does), then an increase of testosterone will make M2F crossdreamers horny. But at least parts of their "wiring" is feminine, so the resulting arousal leads to feminization fantasies instead of the stereotypical "Me Tarzan, you Jane" behavior.

If you change the testosterone/estrogen balance by adding estrogen and/or anti-androgens, the sex drive diminishes and the feminization fantasies become less urgent. The brain remains as feminine as ever, though. Taking estrogen does not "cure" you.


The point of telling you all this is that concepts like sex and gender are highly complex even before you start talking about upbringing and the effects of the surrounding culture.

The confusion and dysphoria felt by crossdreamers regarding their gender identity are likely caused by a combination of genes, hormones and receptors that lies at the outskirts of the statistically normal distribution. Given that our culture has no language or roles that could help these men and women, they find it hard to make sense of their fate.

Roughgarden says this about the gender flexibility of a system based on XX and XY chromosome configuration:

"Although the genetics of transgender expression are unknown and, in human at least, may be superseded by late embryonic and early post-natal developmental experience [i.e. non-genetic influences], transgender bodies are fully consistent with an XY system of sex determination. Indeed feminine males might easily be feminine enough, and masculine females masculine enough, to count socially and to identify as women and men, respectively, even though they possess XY and XX bodies." (pp. 214)

Nature and nurture

In addition to the effects of genes and hormones recent research also indicates that human development may be even more complex than this story seems to tell us.

First of all genes are not stable. They can be turned on and off due to external factors. Secondly the mental state of a person, which again is influenced by his or her life situation and quality of life, does influence hormone production.

But that is not all. It turns out that the brain is much more flexible than originally imagined by researchers. They now talk about the plasticity of the brain. The brain is changing according to the way we use it. To what extent this may influence our sexuality or gender identity is unknown.

What is clear is that any simple explanation of gender identity is bound to be wrong. There is no one to one relationship between one factor (being that the X and Y chromosomes, one brain area or one feminine or masculine "essence") on the one hand and sexual orientation and gender identity on the other.

Nature is a DJ

Let me get back to the mixing table metaphor. Nature is a record producer that loves variation. There are not two human beings that are completely identical, not even identical twins. Every human being is a unique remix of the song of humanity. Sexual reproduction is important, as it makes the mixing possible, but Nature does not give a damn about our understanding of gender roles.

When mixing a biological male, she may turn up a sufficient number of female tracks to make "him" feel and think more like a woman than like a man.

Indeed, when you think about it, there is not one man around that is completely masculine, regardless of what cultural template you are basing your benchmark on. The Dalai Lama is clearly a man, but shows a kind of compassion that is often identified as typical female. Margaret Thatcher and Hillary Clinton are both women, but both show an agressiveness and a determination that are often recognized as male.

That being the case, it is not hard to imagine a tipping point where the "feminine" sides of a man become so strong that he is, in fact, a woman, regardless of what "he" has between his legs. At that point "he" does indeed become a woman trapped in a man's body.



  1. Jack,

    Thank you for the excellent description of what happens from conception to birth... One thing that must be pointed out that for most people the chromosomes, genes, and hormones all work together in perfect harmony to produce men and women. There are situations when everything does not work in harmony and the biological result in one of intersex condition which is very rare. Nature tries to "correct" itself as most of the intersex conditions are infertile. The problem with Vilian and Roughgarden is that they do not recognize that the presence or the absence of the Y chromosome is THE deterimining factor in starting the chemical and biological process to become a male or female. Yes, we all start as a XX female egg. That changes very quickly as soon as an XY sperm comes along... A "Y" does make a male.

    Again, you are trying to make the case for making a scale to rate one's male"ness" vs female"ness". That only works if you can convincingly make the arguement that there are 10 or more different "attributes" of being a man or a woman and all of those attributes are equal in weight. Biologically, that just doesn't work. There are males, females, and people who have one of the several different intersex conditions. Nature puts us into buckets, not onto a scale...


  2. @Robyn

    Thank you for a very useful comment.

    When it comes to the biological sex, in the sense of what you have between your legs, kids normally develop into unambiguous males or females. Only a small percentage becomes intersexed. This also means that for most of the time there is a clear correlation between the Y chromosome and getting testes.

    My point is rather that being male or female is so much more than the testes vs. ovaries dichotomy. If that was all there was there would be no transsexuals, no crossdressers no crossdreamers.

    There would be a clear one to one relationship between gender identity, gender role, gender expression and biological sex. This would be the case even if the cultural upbringing determined most of the gender, since the current Western culture at least do not encourage behavior that go outside the role. Culture would bring forth unambiguous gender identities.

    What this research shows us is that different aspects of what it means to be a typical woman or man (which only makes sense on the aggregate level anyway) is determined by different genes, or combinations of genes, receptors, hormones and other factors.

    On an aggregate level they have a tendency to aggregate in one female cluster and one male cluster, but there is a significant overlap between the two.

    To the various variables that may be at least partly be governed by genes are:
    - level of aggression (testosterone)
    - empathic ability (women excel)
    - spatial recognition (men excel)
    - language skills (women excel)
    - sexual orientation (a majority is heterosexual)
    - copulatory instinct (mounter or mountee)
    - social skills (restroom conspiracies)
    - aesthetic preferences (dressing up)
    - communication practices (talk for bonding among women)
    - selection practices as regards sexual partners (going for looks vs wealth)

    These are 10 of some of the attributes that often are allotted to the two genders in a "Men are from Mars, Women are from Venus" kind of way.

    I suspect some of them are cultural, and most of them can be influenced by nurture and culture.

    Still, if they do have some biological basis, it is easy to imagine "remixes of man" where the biological body is male, but while a majority of the other attributes are at the stereoypical female end of the scale. I am, for instance, pretty much convinced that many -- if not most -- crossdreamers have inherited a copulatory instinct that is female. They want to be the catcher and not the pitcher.

    The crossdreamer condition is pretty rare in this respect. Normally the masculine/female variation we find among men leads to a personality that our language and our culture recognizes as male, even if he is on the female end of the scale for one or two of the attributes.

    Among some crossdreamers the mix leads to ambiguity or the genetic man in question is a transwoman.

    So in the end I do not believe that nature put us in buckets. Nor is there only one scale. There are hundreds of scales, and it is the combination of these scales that a man or a woman makes.

  3. Jack,

    When discussing complex issues such as sex and gender, it is very easy to allow the words to blur things together...

    Looking at only the biological, physical aspects of people, we are male, female, or intersex. For most people, male = man, female = woman, and intersex is so rare that most people are unaware.

    Jumping into transgender "science", the core theory is that male does not necessarily = man and female does not necessarily = woman. Male could mean 30% man and 70% woman depending on the various gender markers being used. There can be a huge number of variations of men and women. It could be possible with this theory that male = women (100%). This brings us precisely to your "remixes" and "scales".

    Then there is psychology, the science of the brain, in between everything. Transgenderism is completely self-diagnosed and self-identified. In many cases it focuses on a person's identity, thoughts, and behaviors in relation to their biology.

    The connection I think you are trying to make is that our biology has given us certain genes which contain various gender markers which give us our identity. This is probably a huge over-simplification... This sounds really good, but I don't think there is any scientific research supporting this. However, there has been some research on the pre-natal hormones and brain development. This might be what is really going on... This is not the same as intersex.

    Getting back to various words and their definitions... When we use terms for gender identity like transgender, transsexual, crossdresser, and terms for sexual orientation like homosexual, these are all based on the male/female biological fact. By defition, intersex cannot be transgender.

    I agree that there are natural variations in men and women such as feminine men and masculine women. Thank goodness we are not identical clones of each other! But we all start as male, female, or intersex.

  4. But we all start as male, female, or intersex.

    Or perhaps we are chimera?

    Chimerism has been found to be exceedingly common in humans. Sensitive genetic tests have shown that at least 50-70% of healthy adults are chimeric to some extent.

    “vanishing twins”, i.e., twins that do not make it to full term, are far more common than previously thought. An ultrasound study showed that one out of eight pregnancies was a multiple pregnancy, and this may underestimate the number, as many embryos probably do not grow to the point where they can be detected by ultrasound

    If the vanished twin is female, some female genetic material will be incorporated into any male twin that absorbs her cells.

    Children known to have had a vanished twin are more likely to have gender-confusion issues...

    It is likely that many stem cells, even from siblings, would eventually be rejected as foreign in a developing fetus, or would be weeded out when the child is born and begins to develop a mature immune system.

    However, certain tissues are exempt from this, including those in the brain. This means that stem cells that made their way into the incipient brain of an embryo could stay there safely, even if they are eliminated from other tissues. In fact, they could, and probably do, persist in the brain throughout the life of the organism.

    Female stem cells in a developing male infant’s brain could have profound implications for its ultimate form. Just as much of the rest of the body is shaped by our gender, so is the brain, and tests with rats have shown that hormones alone are not sufficient to masculinize the brain.

    The anatomical differences discovered in regards to homosexual brains, most of which show feminization, could be explained by pockets of genetically female cells, or even a few interspersed throughout areas critical to masculinization.

    Chimerism in the brain is probably more common than in other regions, and does not usually result in homosexuality, but can when cells colonize certain regions.


  5. With regards to Testosterone...

    Since age 35 (I'm 41 now) I've been taking an herbal supplement that coaxes the hypothalamus into producing gonadotropin-releasing hormone (GnRH) which in turn sends signals to the pituitary gland to produce more LH Hormone.

    You are essentially tricking your body into producing LH hormone in youthful levels which increases testosterone production when it hits the Leydig cells of the testis.

    I did this because I thought I could quash my desire for female gender expression if I just had a enough testosterone in my system...

    The product does work BTW...I've not had my serum testosterone levels measured, but there have been a sufficient about of other indicators that make me a believer.

    Still it has not done a thing to quash my desires for female gender expression; hormones are not sufficient.

  6. @Robyn:

    My presentation is clearly an oversimplification, but I think you and I are closer than you might suspect.

    My point is that the "sliders" (variables) can be moved by genes, hormones, receptors and other factors, even pyschosocial variables. Within that story your point about pre-natal horomones and brain development fits as well.

    The reason I bring up the genes, is that the mere complexity of pro-male, anti-male, pro-female and anti-female genes, opens up for a lot of variation that might explain why, for instance, the pre-natal hormonal environment might vary. But there might be other explanations as well, from virus-infections, the emotional state of the mother, what she is eating etc. etc.

    The truth is that we know too little to draw any final conclusions at the moment.

  7. Yes, I agree with Jack. There are an unknown combination of several factors- hormonal,receptors,psychosocial, everything, that makes us gender-variant. What is worse is that the reasons can even vary from one individual to another and so, the number of independent variables is extremely large. While for some, it may be due to hormones, for some, it could be due to androgen/estrogen insensitivity.
    But, one thing is for certain. We never become "feminine" or more "masculine". We are born with out individual traits and we must live through them. All our traits are innate. Of course for social reasons, we might try to reprogram our brains, but, usually that yields more unhappiness. So far, I have not heard any gay man or woman who has been able to overcome same-sex feelings completely even through drastic therapies and also no transgender who has been able to druive away cross-gender desires by measures like electric shocks.
    Which indicate beyond doubt that our traits are inborn and are not to leave us as there is no mental ailment to be cured.

    BTW, I was recently going through an article of submissive sexual fanatsies of women.
    I identify with most of these traits of women, except that in my fantasy it's a woman doing it with me as lesbian.
    What I discovered was that despite being straight guy I am naturally way inclined to being a 70% woman myself. Most of my day to day thoughts and fanatsies are feminine, I know that. I have never crossdressed or felt too strongly that I need female anatomy or something, but, surely, I am way too feminine to be a real man.

  8. Christy,

    There is a lot of scientific and ancedotal evidendence that increasing post-puberty testosterone does nothing to diminish the desire for female gender expression. If it did, then there would hundreds if not thousands of suffering wives of TGs who would be pushing their husbands into doctor's offices for testosterone... As a matter of fact, if the desire for female gender expression is sexually based, additional testosterone would only increase the desire...

    Also, chimera are very, very rare, not 50% to 70% of healthy adults as the article states. If 50% of adults were chimera, then every criminal case and paternity suit based on DNA would have to be thrown out. Our legal system would be in shambles! Chimera are more rare than intersex and might even be the root cause of some intersex conditions. There are several other problems with that article as well that I won't go into as it is off-topic...


    Yes, we are close in how we see things... I do agree that there are many, many factors that go into who we are. Trying to figure out all the different factors, what they influence, and how much influence will keep scientists in many fields gainfully employed for a long, long time doing research... We do not know what we don't know...

    The key point about all these different factors and the entire nature vs. nuture debate is what does each individual do with the all the various factors, many of which cannot be changed... Do all of these factors handicap us or help us?

    For example, I may like to think of myself as a member of the British royal family even though I am an American. I try to conduct myself as royalty and I would like everyone to treat me with the honor and respect of someone who is royalty. Even though genetically I am not and cannot be British royalty, many of my genes seem to make me very royal as well as most of my childhood experiences. I feel very much that I am royalty even though my chromosones aren't quite right. Would you treat me like royalty? What would happen to me if I knocked on the front door of Buckingham Palace demanding to be let in because I am a member of the British royal family? How could they not let me in?

    Even though the strongest, most burning desire in me is to live my life as British royalty, I doubt very much that I will ever be able to achieve my dream...

    So do I wander around aimlessly through life bitter and depressed because all I want to be is royalty and Buckingham Palace won't let me in? Or do I take my desires and dreams and funnel them into something that makes me a better, happier person? Could I be happy by just being royalty at the occasional Renaissance Faire?

    Finally, with all the various "variations" in the gender spectrum and looking at all the different things that can and sometimes do go sideways pre- and post-natally, it amazes me that so many people have absolutely no questions or issues about their gender, gender identity, sexual orientation, or gender "dreams". Personally, I wish I could wake up some day and have no gender issues or gender "dreams" at all...

  9. Christy, I started taking herbal estrogen (black cohosh) for the opposite reason you were taking testosterone. I wanted to increase my sense of femininity. But, I was shocked to find out that it actually decreased my mental desire to be feminine even as in was physically changing me. If I stop taking it the desire quickly returns.

    My take on it is that when I'm not on estrogen, my brain is out of sync with who I'm really suppose to be. Taking estrogen gets me on track and since I'm where I'm suppose to be the craving goes away.

  10. I think genes and hormones have a lot to do with a man's desire to become a woman, I can grow facial hair but it takes months to become barely noticeable, I looked like a kid for a good chunk of my teen years, only hiting puberty at about 16 years old, my face is not very masculine and my hips are wider than the average male hips, and I'm not even fat, I'm not sure about what of these traits are controled by hormones or genes, but I suspect my hormones might be a little off from average male levels.

  11. Robyn P,
    I liked your comparison of gender issues with the royalty gene.
    Yes, this rings true for me absolutely. Very often I have felt I want to be treated like a girl and not a guy. I wanted to be seen in an more effeminate manner by everyone,though I was also surprised that I liked that despite being in male body. But, soon I found this was my innate nature. I did not have any abuse or something which made me feel so. My genes dictated my desires.
    But,since people (especially girls) treated me as guy, I did wish to change my body so that I did not have to bear this way of treatment from others. Later, however, I found that yes, there are people who would treat you exactly the way you want to be!!
    Yes, even if your male, there will be someone who would let you be the "girl" in bed and will give you all respect and will even love you for that you identify as.
    By your example,yes,you could as well be happy being the royalty at the renaissance fair without being the ideal British royalty member.Because its the respect/treatment you need and there are plenty who will give you that just for being the renaissance royalty. You don't at all need the real thing to be the happiest.

  12. Sorry I haven't set up an account yet, I'm Sean.

    Something bothered me about Robyn's first comment and I've spent a few days trying to work out how to word it. While mulling it over her other comments helped refine the thought a bit.

    The statement was the 'nature puts us in buckets...' line. The flip answer is that nature most certainly doesn't, because buckets are an invention of man... a device used to hold an assortment of things together that wouldn't hold together on their own.

    The category system being used (male, female, intersex) is defined by us, not nature. Nature gives us each a collection of traits that sometimes are fertile and sometimes aren't. We don't look at a non-fertile woman and say she isn't one because she's not fertile.

    Look at the case of androgen insensitive males. Prior to being able to test for XX or XY they were just women. Now you have folks saying they are just men with a condition because we can identify a difference. What if we do find a difference in brain chemistry down they road for trans folks. Will we start issuing apologies?

    The issue with the bucket and the royalty examples are both are on/off. Neither dealt with what to do with the intersex folks. Say, what if they found out you were British royalty, at least genetically. How would you feel if they still wouldn't let you in because no one would acknowledge you?

    As long as folks are saying there are only two real genders and the rest are just sick people, then the best anyone who's not male or female, even if only in their brain, can hope for is a day at the ren faire. I would hope we would want better of our society.

    Change is hard, change on a societal level is harder still. That doesn't change the fact that we are going to have to make the effort if we want to be treated as anything other than an illness. Homosexuality is twenty to thirty years ahead on that road and still fighting, but they rarely have to fight their own on whether their orientation is real.

  13. Anonymous,
    I do agree with you mostly with the thing that nature does not put us into buckets. Also when I talked of agreeing with the royalty concept of Robyn P, I just mentioned about those transgenders who are not real women with strong dysphoria.
    I personally am a male lesbian but I would not transition just because I feel I would be better off as female.
    The reason is that transition is a very painful and expensive process one can take only as last resort. Unless one identifies as full woman on the physical level, it is always unwise to end up transitioning.
    But that does not mean TGs who are not full women are mentally sick. They are having a mix of traits and that clearly shows how Robyn P's bucket concept is wrong.The royalty gene might
    be present full or as a mix. Say, a person is fully of British royalty but born in America.
    While another perso
    n is having a British royalty trait because he is of that family, but still he is born in America and has some American traits as well.
    The former would be happy to transition. What about the second individual who is trapped in a mixed identity? Can he give up one part for the other?

  14. Jack,

    Your statement about the 10 or more gender attributes being " ...cultural, and most of them can be influenced by nurture and culture," has been disproven multiple times. As a matter of fact, research has shown that nurture and culture do not have any impact on one's gender identity.


    When I spoke of "buckets", I was referring to the chromosones only. Not to anything else. Man did not create these buckets. Man only named them based on what was seen in nature.

    To clarify what I mean by "buckets"... People are born with XX or XY chromosomes. In some RARE instances some people have additional chromosones and are intersex. They are not a third sex. They do not represent a "sexual spectrum" of variations. This is basic, fundamental biology. I am not making this stuff up!

    Having a XX or XY chromosome has NOTHING to do with sexual orientation or gender identity. Each X and Y chromosome contain different sets of genes which are sometimes conflicting. There are rules that nature follows to settle these genetic conflicts.

    The chain of human development from start to finish:
    Chromosones -> genes -> hormones -> pre-natal environment -> childhood -> puberty -> adulthood. Each step in the process adds more and more variations into human identity and behavior.

    Jack has been posting many good articles trying to make some sense of how genes and hormones might be involved with sexual identity and gender identity.

    The problem is that science is running into a wall with genetic research. With the mapping of the human genome complete, no genes have been identified directly linked to sex or gender identity.

    However, there have been several genes identified that cause intersex conditions. That is, someone may have XX or XY chromosomes but have a gene that is not working correctly causing the body to develop differently. In some intersex conditions, the baby is born needing immediate medical attention.

    Research linking hormones to sex or gender identity has been inconclusive at best...

    Looking at autogynephilia, is it a type of sexual identity just like being hetrosexual or homosexual? If so, then science may never find the root cause of it.

    If we look at ourselves, why are we only attracted to a few people? Why aren't we attracted sexually or emotionally to every person on the planet? What is it in us that naturally filters out billions of people leaving us only attracted to a select few? Have you ever been with someone who you wanted to be attracted to but the "magic" just wasn't there?

    Jack said, "The truth is that we know too little to draw any final conclusions at the moment." We may never be able to find any conclusions...

  15. Jack,

    There is a good link I found which just attempts to uncover the extremely complicated mystery behind the science of gender identity and sexual orienation. Though nothing can be proved to be absolutely true here, it shows how complicated our brain wirings can be!!http://thatgayguysnewblog.blogspot.com/2010/04/cause-of-homosexuality.html

  16. @jogols

    That's a good one, and yes, that story is very much in line with what I am working on here. Definitely a good read!


    There is one thing in this very fruitful discussion that i find a challenge. I argue that gender identity (the feeling or experience of being either man or woman) is caused by a mix of different variables.

    But is there one variable that is more important than others? Is there a part of the brain that harbors gender identity, in the same way (I presume) as others are the root of sexual orientation or copulatory instinct?

    If that is the case, it would be possible to think of an XY male that identifies as a man, but where all other traits were typical male. I must admit I am unable to imagine such a person, but it is an interesting thought.


    You bring up a related question. The relationship between looks, hormones and gender identity. Is there a correlation between feminine looks and a feminine soul? I very much doubt it, but it is worth a post of its own.

  17. I think I am a man who identifies as male but most of my traits are typically female. I am very much sure of that. I recently even posted a question on this in yahoo Answers

    You see, my most basic traits are very womanly, I think like woman most of the time. My romantic thoughts are mostly feminine.
    But still, for some reason my brain identifies as male. I don't feel like having a female body but I am sure I don't intend to have a macho outlook either.
    In short, I am not transsexual but essentially I am living the life of a typical female in a male body, which i also feel comfortable with!!
    So, I suspect the part of the brain that gives us gender identity is different from the part which gives us masculine/feminine traits.

  18. Robyn, there's one flaw with your chimera skepticism. That is the sheer volume of shared DNA between both original twins. While there will certainly be some variance between the two twins, you could just as likely find as much as 90% or higher shared DNA between both twins.

    The end result would be that it would be entirely possible for a healthy human being to be a chimera and for it only to show up as something barely noticeable on a DNA test.

    Because of this, I'd argue that probability makes this issue far from open and shut.

  19. Nice blog. I like the way you thoroughly research everything.

    Nevertheless, I do have one slight quibble, your use of the word _proof_ as relates to science.

    Nothing is ever proved in science, only supported by the evidence, not supported by the evidence, or disproved. No theory, hypothesis, or law is capable of reaching the finality of absolute, certain truth, as science is ultimately based on inductive reasoning, and so we may always find a counterexample to our attempts to explain the natural world.

    Does this mean that science is useless? No way! Science has brought us many great things and has been very productive, but the good thing about science is that it realizes its limitations.

    Instead, in determining the weight of a theory, you should look at which theory has more supporting evidence: AGP has little evidence supporting it, and many of the studies conducted raise serious questions, such as biased interpretation of results and lack of controls; whereas, the biased-interaction theory (which allows for a biological basis) has garnered a lot of evidentiary support over the last decade or so, and seems to be a very productive explanation of transsexuality (in terms of making predictions and finding evidence).

    Don't sell yourself short by demanding absolute proof; if you expect absolute proof for any scientific theory or law, whether it be evolution, gravity, thermodynamics, or any other, then you will be waiting until the end of time.

  20. To clarify, by AGP in the above post, I mean Blanchard's transsexual etiology, not the existence of AGP, which is supported by the evidence.

  21. @cornince

    I agree completely. Science is constantly developing, scientists are human like the rest of us, sharing cultural prejudices and preconceptions, and the world is far to complex and systemic to be reduced to sinple formulas. What we have to do is to use our critical sense to discuss what seems to be the explanation that makes most sense given the present observations. As i have noted elsewhere there is too much that does not fit with the agp theory.

  22. This comment has been removed by the author.

  23. Christy's chimera theory may have some truth to it. Recent research indicates that most people are chimeras.



Click here for this blog's Code of Conduct!

Discuss crossdreamer and transgender issues!