"yep, why does that bother you ?"
It just seems like an ignorant thing to say. We already know that older brothers increase the chance of being born gay by 33% for each brother (and this has been replicated and is accepted in the scientific community). So for at least 15-30% of the population there is no rationale for the use of "disease". I thought you were being insincere because you offer no evidence. Suggesting behaviour is caused by disease can certainly influence public prejudice and may contribute to the prevalence of hate crimes, so such a suggestion ought to be accompanied by evidence. Would homosexuals be barred from public jobs (such as teaching) because some parents think their child might get "infected" with a "gay virus"!? I think that any unfounded assertions which increase stigmatization against an already stigmatised group is unethical and in poor taste. Your public record on SI of dividing people into we (good) and them (bad) groupings (witness your irrational diatribes against "liberals") lends suspicion to anything you say.
It seemed to me that you were willfully making unfounded assertions while bypassing the genetic evidence. However, feel free to prove me wrong by producing evidence that a virus comes into large families of older brothers and begins to affect the sexual expression of new offspring. Thanks!
Big brothers, immune mothers
Many scientists believe that exposure to hormones during pregnancy heavily influences sexuality. Hormones are chemical messengers, released by certain cells to affect the growth and development of other cells in the body. During pre-natal development, for example, the sex organs in a foetus can recognise testosterone, which will switch on genes to make it male.
Aside from a few superficial differences (among them penis and ring-finger length – both longer in homosexuals), gay and straight men’s bodies appear the same. The exception is homosexual men’s brains, which show remarkable similarities to the brains of heterosexual women, suggesting that sexual orientation depends on the effect hormones have on the developing brain.
But these two factors only go so far in explaining how homosexuality develops. “People assume that all of the biological influence on sexual orientation is either genes or hormones,” says sexologist Ray Blanchard from the University of Toronto. “They might account for the lion’s share of variance in sexual orientation, but it looks like there’s some other bit that requires a third biological mechanism.”
In 1996 Blanchard and Professor Tony Bogaert revealed a peculiar phenomenon: the more older brothers a boy has, the greater their chances of being homosexual. This ‘fraternal birth order effect’ meant that each subsequent brother increases the odds of being gay by 33 per cent. An only child has a two per cent chance, but with 10 brothers the odds are over 20 per cent. But why the increasing odds? Blanchard believes it’s related to how a mother’s body protects itself when pregnant with a son.
“There’s only one system in the mother that would have the ‘memory’ to know how many male foetuses she’s previously carried: the immune system,” says Professor Blanchard. According to his theory, a mother’s immune system keeps track of the number of sons she’s already had, producing antibodies to protect her against male-specific proteins entering her bloodstream, which often occurs during childbirth. As the mother’s level of immunisation increases with each son, so too do the chances of variation from typical sexual orientation as, in theory, the mother’s antibodies could cross the placenta and neutralise proteins that her son needs for normal sexual development.
Many of these male-specific proteins are found on the Y chromosome, DNA that’s foreign to females. “A lot of male-specific proteins are preferentially expressed in the testes and have a crucial role in sperm development,” says Blanchard. “Some are expressed in the foetal brain for reasons that no-one has established, but you wouldn’t expect them to be expressed without a reason.”
Blanchard believes that homosexuality is “100 per cent biological”, and estimates that the fraternal birth order effect accounts for 15-30 per cent of gay men in the population. So what explains the rest? |
