Via the National Institute of Medical Research I have learned of a major breakthrough in the understanding of how mammals (at least, but remember that other types of animals have very different sex systems to ours) develop major sex characteristics. We have known for a long time that physical sex is much more complex than simply having XX or XY chromosomes. According to this article we know understand the exact mechanism by which a body will develop either testes or ovaries. Of particular importance is the fact that this mechanism involves a gene that is not on either the X or Y chromosome, and is active for only a very short period in the embryo’s development. There are therefore definite possibilities for things to go wrong in an embryo with perfectly normal X, and Y if it exists, chromosomes.

Even more startlingly (and potentially annoying for feminist separatists) is the following:

The research challenges several long held assumptions, such that female development happens by default, or that once formed, mature tissues are immutable or fixed.

Really we shouldn’t need this sort of discovery to put an end to the nonsense that human beings exist in only two, mutually exclusive, genders, and I don’t suppose the religious fundamentalists will believe it anyway, but hopefully it will help convince courts and governments.

Medical science being what it is, much of the talk around the discovery is about how it may help us “cure disorders”, but equally it opens up some fairly radical possibilities for gender medicine. My position, as ever, is that brains are much more complicated than bodies, and we should apply whatever treatments help the patients be happier as themselves rather than try to enforce social norms and expect the patients to adjust mentally.

(Hat tip to Sarah Graham and Christine Burns via Twitter).