h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

http://www.guardian.co.uk/science/2008/jun/16/neuroscience.psychology

"Striking similarities between the brains of gay men and straight women have been discovered by neuroscientists, offering fresh evidence that sexual orientation is hardwired into our neural circuitry.

Scans reveal homosexual men and heterosexual women have symmetrical brains, with the right and left hemispheres almost exactly the same size. Conversely, lesbians and straight men have asymmetrical brains, with the right hemisphere significantly larger than the left.

Scientists at the prestigious Stockholm Brain Institute in Sweden also found certain brain circuits linked to emotional responses were the same in gay men and straight women."

Also on the BBC site:

http://news.bbc.co.uk/1/hi/health/7456588.stm

Interesting. I think it's the first time this difference has been observed in live subjects.

Here's a good, readable book on the matter: http://www.amazon.co.uk/Separate-Creation-How-Biology-Makes/dp/0553407287/ref=sr_1_6?ie=UTF8&s=books&qid=1213693409&sr=8-6

Am I the only one who is afraid that this is going to somehow be twisted into Gay men must think like women?

Another idea I thought of just as I clicked post is what about bisexual brains do we(I'm actually still confused on my sexuality but think I fit there) have brains that are part way between men and women or brains that are like straight mebers of are biological sex or what?

My brain hurts....

Ooh I'm intergender, how do I come out of this? Does my brain change along with my gender or what?

I asked my GP why am I gay, his answer I was born gay, and the post 1 of this thread is true according to my GP they scanned a gay mans brain and a straight mans brain to fine gay guys have a gene normaly found in females brains, so am I 1/2 male and 1/2 female? But the thing is if I was 1/2 female why am I not bisexual yes I've had girl friends but nothing happend. I even typed in google on my mobile phone "Why am I gay" And I got all this strange stuff. Cause you get some nutter on the web @ss.

At the PCS* LGBT seminar last weekend an interesting angle came up during a discussion about trans. issues. It was pointed out that, although the sexuality and gender identity are increasingly seen as being unrelated, there is perhaps a commonality in the middle of it all: gay, lesbian, bi and trans (in all its different flavours) people have all, to some extent, rejected the stereotypes of their physical gender of birth.

I wonder if a study similar to that in the first post here has been done to look at trans people too? The results could be interesting.


*PCS = Public & Commercial Services union.

I don't know that sexual orientation has anything to do with physiological specificities, and I don't care much about this.

I have never really bought the "some are straight, some are gay" view: I rather like to think that there is a continuum of possibilities between the two: some might be absolutely exclusively straight (a friend of mind almost feels physically ill to the *idea* of smooching another bloke), some might me mostly straight, but "in the right circumstances, and with the right chap, who knows?", some might be right in the middle, some really feel more at home with same sex partners but wouldn't say know to a straight invitation if it was well put, and some just fall in the other end of the spectrum and wouldn't touch the opposite sex with a stick, even in a non-sexual way... What does that say about the relative sizes of their two hemi-brains?
Maybe us poofters got a bigger right brain just because we use it more, after making friends with a few artists at the local gay club?

And assuming my theory makes sense, how much of a "gay chromosome" (which would be, assuming it exists, either here or not here) would you have if you are just somewhere between the two extremes?

C.L.

As to the 'gay Chromosome' or 'gay gene', Its probably over-simplistic to think of something as complicated as human (and animal) sexuality to be controled by a single* gene....
Rather like most complicated genetic traits there'll be a whole host* of genes involved... some with very slight* influence, some with more influence.... It'll probably be a combination of having 'enough' of these genes to give rise to either 100% straight, or 100% gay, individuals.... of course, this would fit in nicely with my (and others here) views that most* people are somewhere inbetween the two ends of the spectrum.... IN this case someone who's exactly* 50% in the middle, I.E., equally atracted to both sexes, has a combination of the genes which leads to a mid way position as it were...
Of course, like most* genetics, its probably not as simple as that; There may be one very* strong gene, which if you've got it means you are sitting at one end of the spectrum or the other... But which, if you have other* genes, will then vere slightly away from the end that the first gene puts you at.... etc.....
Of course... Genetics alone probably isn't sufficient as a lot of it is suely down to society and socialisation and such like factors.... Someone with 'gay tendancys' but living in a community/society where its really* 'frowned apon', might never express those feelings, or even in some cases realise they have them, as their social 'education' would make them not ever consider having such feelings or thoughts...

Personally being bisexual well varyingly so at differnt times to differnt extents and 'ends', I like to think I'm just 'well balanced'

I think that chemical enviormental influences, such as pre-natal hormone exposure also play a role.

Genes and environment always interact.

As has it ever been as will it ever be.

DNA produces proteins (basically) and some of those definitely have things to do with thoughts and feelings (hormones and neurotransmitters for example) but moreso, there's also receptor sites for both of the above, enzymes to synthesise and degrade the same, intracellular messengers. All vital for brains to do their business but it's a rare thing for a protein like a hormone or a neurotransmitter to cause a behaviour, instead what they code for are tendencies to to respond to environmental triggers in certain ways or to reverse that" how genes are expressed modulates how you respond to your environment"

A good example of this the heritability of schizophrenia is pretty well studied but not everyone how has the gene gets schizophrenia, the same is true of depression. (See: Barondes S. Mood Genes: Hunting for the origins of mania and depression OUP 1999) once you get past the genetic transcripts and so on what left to do this modulating is the environmental cues that precursor stressful environments and then (mismanaged) stress responses (eg a panic attack)

And it's not just like there's 1 gene for x, within a population there is a genetic variance of types of the same genes (which is what all that sex is supposedly really all about) are naturally (and sometimes unnaturally) selected, varied and subject to mutation.

So the idea that LGBT behaviour is due to any one kind of genetic set of differences absent environmental factors is an idea we can pretty swiftly discard. Some behaviour is pretty tightly regulated by genetic influences (off the top of my head: (in)efficient adrenaline production), but genes don't cause behaviour. Not like that.