Friday, 12 March 2010

Garcia-Fulgeras and Swaab.

From Latest and Greatest from two of the big names in the Science of Sex and Gender : Garcia-Fulgeras and Swaab.

Sexual Hormones and the Brain: An Essential Alliance for Sexual Identity and Sexual Orientation Garcia-Falgueras A, Swaab DF Endocr Dev. 2010;17:22-35
The fetal brain develops during the intrauterine period in the male direction through a direct action of testosterone on the developing nerve cells, or in the female direction through the absence of this hormone surge. In this way, our gender identity (the conviction of belonging to the male or female gender) and sexual orientation are programmed or organized into our brain structures when we are still in the womb. However, since sexual differentiation of the genitals takes place in the first two months of pregnancy and sexual differentiation of the brain starts in the second half of pregnancy, these two processes can be influenced independently, which may result in extreme cases in trans-sexuality. This also means that in the event of ambiguous sex at birth, the degree of masculinization of the genitals may not reflect the degree of masculinization of the brain. There is no indication that social environment after birth has an effect on gender identity or sexual orientation.
Note though that - Bisexuals may have an apparent change of sexual orientation, and the Bigendered may have an apparent change of gender identity (though I wish they'd call it sex identity). It's neither a strict binary, nor a strict trinary.

Severely Cross-sexed brains compared with appearances will be apparent when young. Milder cases, or cases where the psyche is strong enough to withstand severe societal pressure to conform without cracking under the strain of maintaining the pretence, will manifest later.

But in summary... I could have told them that. I must read it though to see if they have some new data on it. Hopefully so. While it would be nice to do more than just gather yet more confirming evidence, to do something more original, it's still needed at this stage. Yet another meta-study is also good, though not as good as having more data.

What's visible in the free preview is tantalising:
Boys and girls behave in different ways and one of the stereotypical behavioral differences between them, that has often been said to be forced upon them by upbringing and social environment, is their behavior in play. Boys prefer to play with cars and balls, whereas girls prefer dolls. This sex difference in toy preference is present very early in life (3–8 months of age) [1]. The idea that it is not society that forces these choices upon children but a sex difference in the early development of their brains and behavior is also supported by monkey behavioral studies. Alexander and Hines [2], who offered dolls, toy cars and balls to green Vervet monkeys found the female monkeys consistently chose the dolls and examined these ano-genitally, whereas the male monkeys were more interested in playing with the toy cars and with the ball....
What do you call a monkey that plays with a pink Rolls-Royce that shoots missiles, rather than dolls that just sit there, not interacting? Whose reaction to a doll that pees realistically is to try to take it apart to see how that's done? Or would have been, if it didn't look so much like the baby she wanted to have...

8 comments:

Lloyd Flack said...

Agreed. Gender is a grammatical term, not a biological one.

MgS said...

Actually on the gender versus sex, I'm going to disagree with you. Although my reasons are rooted not in the etiology of the words, but rather in the common understandings of them.

The term 'sex' is horrendously overloaded - it potentially - and confusingly - can refer to any of the following:

(1) Someone's physical characteristics
(2) A person's social role. (anyone else remember the awful description of women as 'the fairer sex'?)
(3) The act of copulation itself

Each of these possible meanings can only be derived from the context in which the word is used.

In North America, the third meaning is so laden with the emotional baggage of the puritans that the word itself is almost taboo to speak. (I will hope desperately that it is not so abused elsewhere in the world)

I find it very useful to have a term in the lexicon such as gender which is not so laden with emotional baggage when talking about my own experiences.

Further, having a lexical distinction between gender and sexual identity allows us to talk more intelligently about the intersections of sexual and gender identities while retaining a sense of clarity about the attributes being discussed.

Nat said...

Hey Zoe... I thought this SMH article might interest you:

Sexless in the city: a gender revolution

It's about the first officially recognised sexless person!

Zoe Brain said...

Hi Nat!

I blogged about it a few days ago.
You were and are an inspiration to me.

One thing I didn't notice:
A Catholic ethicist, Nicholas Tonti-Filippini from the John Paul II Institute, said birth certificates should also record no gender in such cases, updated with ''any changes to phenotypic gender''.

He said there was a trend against the practice of selecting a sex for intersex children, which could mean more androgynous people in future.


I'd be most interested in the rest of what he's said. Who knows, maybe some of my remarks to him have had an effect.

This is the one area where Paul McHugh had it right.

Nat said...

Oh! You did indeed post about it. My bad.

Are you going to be in the forum on Wed night?

Zoe Brain said...

Gosh, that's this week, isn't it?

I'm told Mickey (Milton) Diamond will be on the panel too. WOW

Alyx said...

I am glad to see that an article like this has been recently published. However, like what Zoe said, I am disappointed that there was not much new data put forth by the authors (aside from the brain comparisons). I would have liked to see a more in-depth discussion of the biochemistry that occurs during early brain development in utero. Nonetheless, this is certainly a step in the right direction.

Battybattybats said...

"since sexual differentiation of the genitals takes place in the first two months of pregnancy and sexual differentiation of the brain starts in the second half of pregnancy, these two processes can be influenced independently, which may result in extreme cases in trans-sexuality."

It's recognition of this bit that I'd like from some of those amongst the HBS crowd that are often irrationally hostile towards many of the people on the gender diversity spectrum. That the mechanisms for biological causation may include degrees. And when we deduce what a mild case might be like it surely predicts the spectrum we find of sex and gender diverse groups. Simple enough, logical enough, testable to boot.

And crucial science to get fair treatment of many people.