Questions about homosexuality

Maybe.
The two interact at many levels. It's hard to tell sometimes whether human behaviour is genetic or learned. Bit of both, generally.
Matt Ridley's book "Nature via Nurture" is excellent on this.
 
Not that it matters much, but I'm gay and have kept my ears open for discussions on this subject for years. I'll toss a few points out without evidence - I'll try to back them up soon after some surfing...

I have heard of some species in which higher-than-proportional increases in the occurrence of homosexual behavior are observed as the population grows.

I believe that I've heard that there is a genetic propensity for being homosexual that has been supported by some identical-twins/fraternal-twins studies.

I've heard of a suggested mechanism for differentiation between the brain of a gay male versus that of a straight male: The brain is masculinized by significant increases in testosterone at two precise windows of time during gestation. If the testosterone levels during these periods are too low, the brain will not fully masculinized. I've also heard that a person whose brain is overexposed to testosterone, or hypermasculinized, may be susceptible to autism. I was under the impression that both the child and the mother may be involved in under-, or over-, or mistimed-production of testosterone.

There are some species in which greater genetic advantage is gained by nurturing one's sibling's offspring than by nurturing one's own (Stephen J Gould, I believe). I think a similar argument might be made regarding homosexuality.

I believe that, while I will not have any children, my sister's and brother's children have approximately as much in common with me genetically as they do with each of their grandparents (may be wrong - first time for anything). So, while I don't have any children, I have the genetic equivalent of 7 grandchildren, and more time and resources to nurture them than if I had children of my own. As a result, my parent's grandchildren are fewer but better nurtured than if I had had children.

I hope that this example raises two thoughts - being childless is not the same as not participating in The Great Game, and there may be some selective advantage to homosexuality.

Good discussion. I'll dig around and find out more...
 
Yes- there's statistical evidence that gay men tend to have more older brothers than straight men for example. A baby is a foreign body from the POV of the mother's immune system- half the genes are from the father, after all. It could be that the mother becomes "vaccinated"as it were against the foreign cells , so that with each successive pregnancy the biological response of her body is different. If the hormone levels are different during pregnancy, there could be a different degree of masculinisation of the foetus. (All mammals start female, what happens afterwards dpends to some extent on the mother's hormone levels in the first few days of gestation.

Straw poll- Complexity- got many big brothers? (Damn, this statistics is easy!):)

It's hard to see how homosexuality could be a selective advantage for the individual. It certainly might be for the gene though.
Hey- you want a selective advantage, get along to an assisted fertility clinic, donate semen. (They'll pay if you're desperate).
You get-
1.Free dirty mags. Hmm- better take one of your own.
2. A tenner a whack. (Is that the right word, I wonder?)
3. The chance to have up to ten kids which someone else pays to bring up.
4. And if you lie thoroughly and convincinly about who you are, not only will they not arrive on your doorstep in 20 years, but you can wangle it so they arrive at your worst enemy's.
 
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By the way, just to complicate the issue even further, the latest 'buzz' word in genetics circles is 'matrix'. Matrices are collections of genes that together influence a trait. No longer do you have a gene for a given characteristic, but rather a 'matrix', which includes a whole number of genes that account for coding, interpretation, levels of expression and so on. Recent efforts have begun to look more at the linkages within and between matrices. Hence you won't have a gay 'gene', but a gay 'matrix'. This matrix can then further be influenced by the environment, much like oncogenes are pre-cancer genes. Having them does not mean you have cancer, but it might indicate that given the right environmental factors you have a higher than average chance of getting it.

Athon
 
By the way, just to complicate the issue even further, the latest 'buzz' word in genetics circles is 'matrix'. Matrices are collections of genes that together influence a trait.
Matrix, good word. I heard it explained as a bunch of switches. Perhaps analogous to the mixing board for an audio technician. Combinations of which switch is up and which down can be mind boggling.
 
I recommend the book Endless Forms Most Beautiful: The New Science of Evo Devo and the Making of the Animal Kingdom by Sean B. Carroll.

This is where I learned the most about the DNA switching mechanism, as well as a lot more. It is a wonderful book about evolutionary development.
 
Not to derail or anything, but this is what I have always found puzzling about homosexuality. I think the essense of what the sexes find attractive about each other are their differences - that the things men find attractive in women are those attributes, both physical and psychological, which are dissimilar to their own attributes and vice versa. Looked at in this way, homosexuality doesn't make any sense. I don't mean this as a criticism of homosexuality, but I think this is part of the reason some people can't wrap their minds the idea of homosexuality. It would seem, if one were homosexual one could plausibly find one's self sexually attractive. I remember a movie I saw where a teenage boy said something to the effect that if he had boobs he would play with them all day long. A homosexual person, in a sense, gets to live that fantasy one would think.
 
Not to derail or anything, but this is what I have always found puzzling about homosexuality. I think the essense of what the sexes find attractive about each other are their differences - that the things men find attractive in women are those attributes, both physical and psychological, which are dissimilar to their own attributes and vice versa.
Nope. There are a whole lot of examples that disprove the "opposites attract" nonsense. What people find attractive varies widely from person to person, and is a combination of genetics and cultural programming. There is no hard and fast rule about what a particular person will find attractive. About the only thing that comes close is that most humans show a preference for regular, symmetrical features with no obvious defects or extreme exaggerations. But there are those who deviate from that general model as well.

And features that in one culture are generally considered highly desirable, are often considered distinctly unattractive in other cultures.

Hence you won't have a gay 'gene', but a gay 'matrix'. This matrix can then further be influenced by the environment, much like oncogenes are pre-cancer genes.
Well, personally, I though The Matrix was pretty gay. I mean, seriously, Reeves has got to be one of the most obvious closet cases I've ever seen. It was clear even as far back as Bill and Ted's Excellent adventure.
 
Soapy Sam - I'm the oldest kid in the family.

Damme! Another lovely theory destroyed by an ugly kid!


Athon- Remember the caution- "A Gene for Z" is shorthand. Apart from HOX genes, it's very unlikely that any single short stretch of DNA is solely responsible for anything much. Each gene operates like one switch in a network. It's effect will vary, depending on the settings of other switches.
Each other switch affects protein production. The presence of protein X may inhibit production of Y. The whole thing is massively re-entrant.

God knows how it works at all (presumably).
The code would be a bitch to debug.
 
Not to derail or anything, but this is what I have always found puzzling about homosexuality. I think the essense of what the sexes find attractive about each other are their differences - that the things men find attractive in women are those attributes, both physical and psychological, which are dissimilar to their own attributes and vice versa.

But only for sex. Apart from where they want to put their jiggly bits men would appear to prefer the company of other men and prefer the company of men with similar behavioural attributes. It is very rare for a man to have mainly women as friends.

Looked at in this way, homosexuality doesn't make any sense. I don't mean this as a criticism of homosexuality, but I think this is part of the reason some people can't wrap their minds the idea of homosexuality. It would seem, if one were homosexual one could plausibly find one's self sexually attractive. I remember a movie I saw where a teenage boy said something to the effect that if he had boobs he would play with them all day long. A homosexual person, in a sense, gets to live that fantasy one would think.

You do find yourself sexually attractive - if you didn't you wouldn't be having sex with you!

Also an example of the fact that men do not "instinctively" find other mens sexual apparatus off-putting is that most pornography movies aimed at men also features men. If the men found that repulsive then they wouldn't be getting much satisfaction from the pornography and consider how popular pornography is.

When we drop our culturally acquired blinkers (such as the still very common "oh poofters the very thought makes me sick") we soon realise that homosexuality is very, very similar to heterosexuality.
 
Homozygous/heterozygous

If sexual preferences are acted upon, homosexuality would seem to rule out reproduction, which is most certainly not adaptive in any obviously immediate way.

Passing off the existence of homosexuality as a meaningless and incidental variation is utterly ridiculous.


Homoexuality genes (if there are such things) can be adaptive. Look at sickle cell anemia. Although the homozygous individual is ill and will most likely die before puberty, the heterozygous individual is more resistant to malaria, a highly adaptable trait in subtropical countries. Moreover the gene will spread in the population, increasing the occurance of homozygous individuals, and hence, sickle cell anemia.
I am not saying that homosexuality is genetic, but it can be imagined that heterozygous individual (that is, he/she has one gay gene) can have a slight advantage to the rest of population, wherea the homozygous individual will be gay, an hence a potential genetic dead-end. For example, as the stereotype says, gay men tend to be more empatic and affectionate. Furthermore the heterozygote will increase the occurance of the gene through, say, kin selection. Moreover, the gene will spread in the population, thus increasing the number of homozygous.
Let me know if this makes sence.
Oh, and sorry for the spelling, it's my third language.

Cheers
 
One of the most influential studies on the genetics of homosexuality was done by Dean Hamer and his co-workers at the National Cancer Institute in Washington DC (1993). Hamer's research involved studying thirty-two pairs of brothers who were either "exclusively or mostly" homosexual. None of the sets of brothers were related. Of the thirty-two pairs, Hamer and his colleagues found that two-thirds of them (twenty-two of the sets of brothers) shared the same type of genetic material. This strongly supports the hypothesis that there is an existing gene that influences homosexuality. Hamer then looked closely at the DNA of these gay brothers to try and find the region of the X chromosome (since the earlier research suggested that the gene was passed down maternally) that most of the homosexual brothers shared.

He discovered that homosexual brothers have a much higher likelihood of inheriting the same genetic sequence on the region of the X chromosome identified by Xq28, than heterosexual brothers of the same gay men.

Other studies have been conducted that look at twin brothers rather than brothers of different ages. Bailey and Pillard (1991) did a study of twins that determined a 52% concordance of homosexuality in monozygotic twins, 22% for dizygotic twins, and 11% for adoptive brothers of homosexual men. These results, like Hamer's, provide further support for the claim that homosexuality is genetically linked.

http://serendip.brynmawr.edu/biology/b103/f97/projects97/Newman.html

There would be no reason why the twins of homosexuals would be so likely to be homosexual too if there was nothing genetic to it. Unless they just happen to decide to be gay like their twin brother *rollseyes*
 
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Nope. There are a whole lot of examples that disprove the "opposites attract" nonsense. What people find attractive varies widely from person to person, and is a combination of genetics and cultural programming. There is no hard and fast rule about what a particular person will find attractive. About the only thing that comes close is that most humans show a preference for regular, symmetrical features with no obvious defects or extreme exaggerations. But there are those who deviate from that general model as well.

And features that in one culture are generally considered highly desirable, are often considered distinctly unattractive in other cultures.


Well, personally, I though The Matrix was pretty gay. I mean, seriously, Reeves has got to be one of the most obvious closet cases I've ever seen. It was clear even as far back as Bill and Ted's Excellent adventure.

Didn't say opposites attract did I? You surely are not saying that it is not female attributes that attract males to females generally. That would be a rather nutty thing to say. And, in fact, cultural notions of beauty are not very different at all. One culture may find saggy breasts attractive and another might find firm, upstanding ones attractive, but they attribute attractiveness in the female to having breasts, generally speaking.
 
But only for sex. Apart from where they want to put their jiggly bits men would appear to prefer the company of other men and prefer the company of men with similar behavioural attributes. It is very rare for a man to have mainly women as friends.



You do find yourself sexually attractive - if you didn't you wouldn't be having sex with you!

Also an example of the fact that men do not "instinctively" find other mens sexual apparatus off-putting is that most pornography movies aimed at men also features men. If the men found that repulsive then they wouldn't be getting much satisfaction from the pornography and consider how popular pornography is.

When we drop our culturally acquired blinkers (such as the still very common "oh poofters the very thought makes me sick") we soon realise that homosexuality is very, very similar to heterosexuality.
Apparently I am not making my self very clear. And, I have to say I never remotely expressed the notion that "the very thought makes me sick". You obviously are reading into what a wrote more than I actually wrote. I guess you are calling masterbation "having sex with you". Well that is a fairly ridiculous notion. Gratifying yourself is not having sex with yourself. I know a number of people who find themselves sexually repulsive and I am pretty sure all of those people masturbate. The fact that there are men in porno movies has nothing to do with the sexual appeal of men to other men. Those men are our proxies in those movies and that is the function they serve. Furthermore, men watch those movies to see beautiful women being penetrated by penises. It doesn't matter who the penis belongs to. Since the users of pornography can not penetrate those women with their own penises they must do it vicariously using their proxies.

Gayness has never been an issue for me and my best friend for many years was gay. Have been in the theatre for some time years ago, virtually every man I knew was gay. Some where dear friends and some were ass-hats, just like everyone else. That doesn't change the fact that there is something obviously different between homosexual sexual attraction and hetero sexual attraction. Straight men are attracted to females because they are women and specifically because they are not men and not merely incidentally. Likewise, gay men are attracted to other men because they are male.
 
Apparently I am not making my self very clear. And, I have to say I never remotely expressed the notion that "the very thought makes me sick". You obviously are reading into what a wrote more than I actually wrote.

Sorry I wasn't trying to suggest for a moment that was your view - that was just an example for what i think are "culturally" created opinions and views not "biological" ones.


I guess you are calling masterbation "having sex with you". Well that is a fairly ridiculous notion. Gratifying yourself is not having sex with yourself. I know a number of people who find themselves sexually repulsive and I am pretty sure all of those people masturbate.

I wasn't meaning masturbation, I was meaning the fact that sex will normally involve your body (which I am assuming in our cases are male).

The fact that there are men in porno movies has nothing to do with the sexual appeal of men to other men.

Yes it does - it means that men do not necessarily find other men sexually a turn off. I've known plenty of heterosexual male friends who have engaged in three in a bed - with there being just one female yet they do not consider that anything to do with homosexuality. Yet it is hard to hold the view that in those circumstances straight men aren't being intimate with other men. There is also (and I am trying to be careful because of the type of forum this is) the fact that males engage in other "sexual" acts with other men that again they do not consider homosexual in nature (the type of masturbatory "competitions" young adolescents are known to engage in).

All these activities actually show that the line between what we tend to call heterosexual and homosexual sexual preferences is not as black and white as we like to culturally portray it as being.

Those men are our proxies in those movies and that is the function they serve. Furthermore, men watch those movies to see beautiful women being penetrated by penises. It doesn't matter who the penis belongs to. Since the users of pornography can not penetrate those women with their own penises they must do it vicariously using their proxies.

Yet the sight of those other male penises does not cause problems (for the majority of men) when they are thinking about sex. Again demonstrating that the difference between a homosexual act and a heterosexual act can be very hard to determine.

Gayness has never been an issue for me and my best friend for many years was gay. Have been in the theatre for some time years ago, virtually every man I knew was gay. Some where dear friends and some were ass-hats, just like everyone else. That doesn't change the fact that there is something obviously different between homosexual sexual attraction and hetero sexual attraction.

I agree there is a difference I just maintain it isn't as much of a difference as we tend to consider it is. (And we note the difference because of cultural reasons not biological ones.)

Straight men are attracted to females because they are women and specifically because they are not men and not merely incidentally. Likewise, gay men are attracted to other men because they are male.

This isn't borne out when we look at other cultures where there may be what we consider homosexual activity between males that will go on to marry and act as we consider hetrosexual men "should" do. (And in what we know of historical cultures.) I think that all we can conclude is that humans like sex with pretty much any human they find attractive and that different cultures tend to express this in different ways.

I think this is a longwidned way of saying I doubt we will ever find a "homosexual" gene or matrix, what I suspect we will find is just genes that deal with human sexuality.
 
I've read it's artificial because in China like lots of countries males are better than females. I'll leave it to you to infer then why there are so many more males than females.


And the ratio, something like 120:100, is horrific.

Yes, all we need is an economic juggernaut lead by a dictatorship, and a half a billion males, a hundred million of which can't get a girl, all angry.

We may live in very interesting times over the next 20 years or so, indeed.
 
Yeah. If all those frustrated Chinamen jump off the top of the wardrobe onto the bed of a Hong Kong hooker at the same time, she'll feel the Earth move.
 
Sorry I wasn't trying to suggest for a moment that was your view - that was just an example for what i think are "culturally" created opinions and views not "biological" ones.

I wasn't meaning masturbation, I was meaning the fact that sex will normally involve your body (which I am assuming in our cases are male).

Yes it does - it means that men do not necessarily find other men sexually a turn off. I've known plenty of heterosexual male friends who have engaged in three in a bed - with there being just one female yet they do not consider that anything to do with homosexuality. Yet it is hard to hold the view that in those circumstances straight men aren't being intimate with other men. There is also (and I am trying to be careful because of the type of forum this is) the fact that males engage in other "sexual" acts with other men that again they do not consider homosexual in nature (the type of masturbatory "competitions" young adolescents are known to engage in).

All these activities actually show that the line between what we tend to call heterosexual and homosexual sexual preferences is not as black and white as we like to culturally portray it as being.



Yet the sight of those other male penises does not cause problems (for the majority of men) when they are thinking about sex. Again demonstrating that the difference between a homosexual act and a heterosexual act can be very hard to determine.

I agree there is a difference I just maintain it isn't as much of a difference as we tend to consider it is. (And we note the difference because of cultural reasons not biological ones.)

This isn't borne out when we look at other cultures where there may be what we consider homosexual activity between males that will go on to marry and act as we consider hetrosexual men "should" do. (And in what we know of historical cultures.) I think that all we can conclude is that humans like sex with pretty much any human they find attractive and that different cultures tend to express this in different ways.

I think this is a longwidned way of saying I doubt we will ever find a "homosexual" gene or matrix, what I suspect we will find is just genes that deal with human sexuality.

Yes, you are right it is not as simple and cut and dried as I might have suggested it is. On the other hand, I would stand by the idea that men, generally, are attracted to the feminine characterists in a woman and find masculine characterists unattractive. And I would define feminine characteristics as those features which men tend not to share and vice versa. Like I think I said, while hetero men may prefer different types of breasts - small or large, firm or saggy, they still prefer their women to have them and to have the defining characterist which designate a person as a woman. In general, men do find masculine characteristics sexually repellent - hairyness, muscularity, largeness, smellyness (just joking, sort of. I sure don't find the smell of a locker room or other men appealling.) Essentially, I stand by my premise that the characteristics straight men and women find appealing are those which they don't share and which tend to distinguish their gender from the opposite one.
 

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