Re: 17 yr old jailed after holiday flirt in Turkey

Following up to Mxsmanic <mxsmanic@xxxxxxxxx> :

Unless is confers a greater advantage to siblings.

How would it do so?
What real evidence is there to support this?


Proceedings of the Royal Society B, DOI: 10.1098/rspb.2004

And why is it so important to prove that homosexuality is genetic?

You tell me, I never said it was.
The rest you can look up yourself.

"BACK in 1993, when Dean Hamer discovered what appeared to be a gene that
predisposed men to homosexuality, he created a paradox. According to
Darwinian thinking, if homosexual men have fewer children than straight men
the "gay gene" should quickly disappear from the population. Yet we know
that homosexuality persists.

So what is the mechanism that keeps the gene in circulation? Perhaps gay
men are good at looking after their straight brothers, who share a
proportion of their genes. That way, the gay gene may be passed on by the
brothers of gay men, even if they themselves have no children.
Unfortunately for this idea, studies so far have found that gay men do not
help out their brothers financially or emotionally any more than straight
men do.

Another idea espoused by Hamer and others is that a gene which predisposes
men to homosexuality might also increase a woman's chances of having more
children. In this way, the reduced likelihood of gay men passing on the
gene would be more than compensated for by women carrying the same gene.
This is precisely what a group of researchers from Italy have found. The
mothers and maternal aunts of gay men had more children than those of
straight men (see "Gay genetics*"). And this difference does not appear in
the father's family.

That the extra children should appear in the mother's side of the family
fits with the idea of a gay gene passing from mother to son on the X
chromosome. However, no simple pattern of inheritance can account for the
Italian findings: the only model that fits is one where several genes, at
least one of which is on the X chromosome, combine in some way to influence
sexual orientation. So, as has been suggested before, it may not be one
gene we are searching for but several.

While the Italian team supports the idea that genes influence
homosexuality, they also caution that genetics is not the whole story.
Their findings confirm that gay men are less likely to be firstborn
children than later-born, and are more likely to have older brothers than
sisters. They also back up previous results that gay men have more male
homosexual relatives on their mother's side of the family. Yet these
factors account for only a fifth of the variance seen in male sexual
orientation. So a boy's experiences are still critical in deciding whether
on not he becomes gay.

These findings, assuming they can be repeated, will not satisfy gay groups
who want homosexuality to be seen as purely a genetic trait. Nor will they
please commentators who see homosexuality as a choice made by "sinful"
people. What they do show is human sexual behaviour in all its splendid
complexity.
From issue 2469 of New Scientist magazine, 16 October 2004, page 3
"



"
* Gay genetics

IF homosexuality is an inherited trait, why do genes for it survive?
Because these genes may make women more likely to reproduce.

Andrea Camperio-Ciani's team at the University of Padua, Italy, asked 98
gay and 100 straight men to fill in questionnaires about their families.
They found mothers and aunts had more children if related to a gay rather
than a straight man. Mothers of gay men averaged 2.7 babies, compared with
2.3 born to mothers of straight men. Aunts on the mother's side had 2
babies compared with 1.5 for maternal aunts of straight men (Proceedings of
the Royal Society B, DOI: 10.1098/rspb.2004).

The team suggests that gene variations on the X chromosome make women more
likely to have more children, and men more likely to be gay. "We think of a
gene for male homosexuality, but it might really be a gene for sexual
attraction to men," says Simon LeVay, a neuroscientist at Stanford
University and a writer on sexuality.

But the "maternal effect" could at most account for only 14 per cent of the
prevalence of male homosexuality, the Italian team cautions. "Our findings,
if confirmed, are only one piece in a much larger puzzle on the nature of
human sexuality."

“We think of a gene for male homosexuality, but it may be a gene for
attraction to men”

--
Tim C.
.

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