Many people might have heard the story that Tom Gabel (of Agaisnt Me! fame) has come out as a transgender (and is planning to start living as a woman). This might lead you to wonder what exactly transgender means and what the science of sexuality has to say about such cases. Transgender, like many sciency words, basically gets its meaning from the smaller words that it consists of. Trans means opposite (as anyone suffering through organic chemistry will know) and gender….well…. here we hit a slight problem. There is no scientific definition of gender, it is not a scientific word and to some extent it is just a social construct. It is usually taken to be some combination of sexual identity and sexual orientation (although I would hesitate to view it this way as it seems to imply that those two change together, which is not the case).

For example, a homesexual (homo meaning one or the same and sexual here referring to the preferred sex partner) does not feel like or desire to be of the opposite sex. Their sexual identity (which is a (more) scientific term referring to the subjective feeling of belonging to a certain sex) matches their actual sex. They simply have a sexual orientation of preferring the same sex partner. So whilst that is a difference of sexual orientation (but not of sexual identity) transgender is an issue of sexual identity: it is basically a disconnect between the physical sex of a person and their sexual identity. These people have a very strong pervasive feeling of belonging to the opposite body and being ‘trapped in the wrong body’.

So why do these differences (of sexual orientation and sexual identity occur)? Short answer: we don’t know. Long answer: it seems to be biological. There has not been any convincing social explanation that has held any weight and all evidence points against the notion that it is simply a lifestyle choice and anyone who tells you it is has no defencible basis in fact. The question then becomes what (biological) mechanism explains these phenomena and it is unlikely to be a simple answer. Having ruled out social explanations many people jump straight to DNA, thinking sexual orientation must then be programmed into their code but it is not an either/or situation and other factors may well play a role. For example, exposure to hormones (likely prenatally) could be a factor. An explanation like this could explain why some pairs of identical twins (identical DNA) report having different sexual orientations (they could possibly have had different exposure to hormones). Research into hormonal exposure has not revealed any obvious answers to questions about sexual identity and sexual orientation but it still may (or maybe not) be a relevant factor.

Honing in to the topic of being transgender there is some (uncertain) evidence to support a more biological aspect. Parts of the human brain are sexually dimorphic; that being a complicated label to mean that there are differences in the brains of the two sexes (for example some obvious ones like the neural control of breastfeeding). One such area is the Bed Nucleus of the Stria Terminalus (the stria terminalus is a small fiber tract in the brain). This nucleus of the brain is large in males (both heterosexual and homosexual) and small in females. However in male transsexuals it is small like in women and in female transsexuals it is large like in men. So it seems to correlate to sexual identity. We have to be careful in interpreting this since it could be a link causing transgenderism, or equally something caused by transgenderism or could also be irrelevant, but it’s a start.

The last thing I will leave you with is an incredible syndrome which, to be honest, I didn’t believe the first time I heard about it (from a friend) but it was later confirmed by a professor in a lecture on sexuality and the brain. There is a (very rare) genetic disorder called 5 a reductase deficiency where the receptor for testosterone does not work in the body, so despite being genetically male (XY) the testosterone can not cause its effects and so the baby is born as a female (which is sort of a default result whenever there isn’t active testosterone). However at puberty a different receptor starts being used (which is functional in this syndrome) and so suddenly the body starts reacting to the testosterone and starts growing into a man. The overall course of this syndrome is a patient being born physically as a girl (with undescended testes) who at puberty starts to grow male sex organs and turns into a man. I would imagine that it is not quite so simple and straightforward but the syndrome does exist.

Interesting Extras

• Although overall very rare, the 5 a reductase deficiency is relatively common in a certain area around South America due to a small gene pool. They call it ‘guevedoces’ which means (pretty much literally) ‘penis at 12’

• People used to think that homosexuality was more related to your mothers side because it seemed more gay people were reported on the mothers side. However this is now believed to be a case of reporter bias. The bias is this: who knows more about their family (going back a while) your mother or your father? Thought so. That doesn’t really tell us very much about where sexual orientation comes from but it is an interesting gender difference.

• Epigenetics means the link between genetics and the environment (meaning environment effects gene experession). Schizophrenia for example seems to have epigenetic influences and sexual orientation might as well.

• There was a theory that each subsequent boy born to a mother had an increased chance of being homosexual (the researchers suggested a hormonal effect where the mothers body reacted slightly differently to each subsequent male child). There is no evidence for this theory (and no real reason to subscribe to it) but if it was true, by about the 4th boy of a family there would be a fairly high chance of them being gay

• Some research has looked specifically for the ‘gay gene’ but it is very unlikely one single gene codes for sexual orientation. Genetics is actually always a vast interplay of many genes and if the answer does lie in the genome its probably not simple.

Quotes

• ‘There is no greater mystery in the world, as it seems to me, than the existence of the sexes’ – Charles Darwin

• ‘An intellectual is a person who has discovered something more interesting than sex.’ – Aldous Huxley

• ‘There is nothing wrong with going to bed with someone of your own sex. People should be very free with sex, but they should draw the line at goats’ – Elton John

• ‘I think what you’re seeing is a profound recognition on the part of the American people that gays and lesbians and transgender persons are our brothers, our sisters, our children, our cousins, our friends, our co-workers, and that they’ve got to be treated like every other American. And I think that principle will win out.’ – Barack Obama