Same sex attraction and the vanished twin: or is it your genes?

I read this article today.  Written by Neil Whitehead, who has written extensively on this subject, it suggests that being transsexual is certainly not genetic.  Well that's a relief anyhow, because it's clear to me that feeling like a man trapped inside a woman's body - or vice versa -  has more to do with some prenatal effect than a genetic predisposition of any kind. Certainly transsexuals are born that way, but  its not written onto their genetic code.

If we seek out a vanishing twin of the opposite sex however, a whole lot of things come clear.  ( I have been in communication with several transsexual individuals who found this explanation a great comfort)  It's a pity that more people working in this field don't do a little research to find out if there are any pregnancy markers, like bleeding or an early ultrasound image of two sacs, among the transsexual group.

Not rocket science I suggest, but sadly no one knows about the signs and indications of a twin or multiple pregnancy that results in the birth of a single baby (Listed on this downloadable document - help yourself, it's copyright free.)

Anyhow, here is some of this excellent article to ponder upon. Clearly transexuality is a very different matter to homosexuality, for it has more to do with who you are than who you might relate to sexually:

Usually transsexuals (and homosexuals) argue that studies have shown their brain microstructure is more feminine (Gorman, 1995; Zhou, Hofman, Gooren & Swaab, 1995). Such studies are notoriously poorly replicable, and provide a very shaky foundation for such a view. The most unequivocal evidence is that brain microstructures are produced by long-continued behaviour, rather than long-established brain structures causing the behaviour. The brain changes physically in response to our behaviour - London taxi drivers have an enlarged part of the brain dealing with navigation, violinists a larger area dealing with movement of the fingers of the left hand. There is no evidence that people are born with brain microstructures unalterable ever after - but there is strong experimental evidence that experience changes that microstructure. Transsexual brain differences would be more likely the result of transsexual behaviour than its cause.

Many transsexuals (and homosexuals) showed childhood gender non-conformity (Zucker& Bradley, 1995). Boys were sissies, girls tomboys. But only a small minority of sissy boys become homosexual and a much smaller proportion become transsexual. Similarly for girls. Early sexual experience may be very important for some boys, but only a minority who have experienced it become homosexual as adults. Distant fathers may be a critical factor in later homosexuality for some boys, but a vast majority of boys with distant fathers do not become homosexual and even fewer become transsexual. There is no one cause, many paths, and many unique experiences.

But there is no evidence for the political case that transsexuals were born that way.

But what if transsexuals were born that way because they received a flood of opposite-sex hormones in the womb, from their missing twin?  Would it help for them to know that?  I wonder.  What do you think?