Via Cheryl Morgan, news of recent research that’s blown holes in a lot of our preconceptions about how the physical sex of a mammal is determined by genetics. I’ll quote Cheryl rather than the article, because she uses less sciencespeak:

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 now 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.”

And near the end of the press release, there’s this:

… if it is possible to change adult gonad type from ovary to testes or even the reverse, it may eventually allow individuals with gender dysphoria, who feel they are trapped in the wrong sex, to change their gonads appropriately rather than having them removed surgically as part of their treatment to undergo gender reassignment.

Another little step closer to living in Iain M Banks’ Culture universe… 🙂