One of the (many) frustrations of writing a lot about sex and gender is knowing that there are a lot of people who are concerned about these issues but who do not, for various reasons, say so.

I’ve written quite a lot about the politicians, of all parties, who have private worries and criticisms about policies and laws intended to benefit transgender people which, however inadvertently, might have implications for women and their legal rights. I’ve also written about the failure of some media outlets, including some (but not all) parts of the BBC, to cover this issue properly.

I am also aware of lots of women in lots of different walks of life who worry about this stuff but do not say so. Many are fearful of the backlash, the accusations of transphobia that could follow. Some of these women are prominent and famous and rich and powerful. The fact that such people keep quiet gives you some idea of the power of fear here.

Fear that silences such concerns means this issue is not properly debated. Some people have deliberately sought to make sure such debate does not take place: see this for the tactics involved.

Yet slowly, slowly, things are starting to change. More people are starting to talk, calmly and sensibly, about a matter of policy and culture that needs more discussion. Bit by bit, more people are starting to see that this is an issue that can and should be talked about.

That turning of the tide has been slow and modest, but today the pace quickened, a lot. The gender debate has seen an event that many people have been waiting for. JK Rowling has spoken.

In a single tweet, the woman who gave us Harry Potter, has quite deliberately entered a debate that many people have avoided for too long:

The reason for the tweet is the case of Maya Forstater, who I wrote about here.

She said she lost her job for expressing her view that human beings cannot change sex and that a transwoman remains, despite their expressed gender identity, essentially male.

You might think that is a statement of biological reality, but Forstater lost an employment tribunal case this week.

I won’t comment in detail on the judgment, beyond noting the judge’s comment that Forstater is:

‘absolutist in her view of sex and it is a core component of her belief that she will refer to a person by the sex she considered appropriate even if it violates their dignity and/or creates an intimidating, hostile, degrading, humiliating or offensive environment. The approach is not worthy of respect in a democratic society.’

Several commentators have concluded that amounts to a judicial prohibition on women stating that people who were born male and who have male anatomy are men, if those people describe themselves as women. I’ll leave it to readers to draw their own conclusions about what that means for free expression and the debate of ideas.

In narrow terms, the judgment might well have a chilling effect on that debate. But the broader effect of the Forstater case is that issues of sex and gender, the implications of transgenderism for society and individuals, are now going to be talked about by more people.

Because JK Rowling, lovely JK Rowling, is involved. JK Rowling who has 14 million followers on Twitter and a good claim to being one of the most popular and even beloved women in the world today. And as a result, people are going to talk about this, and about her.

I do not underestimate the courage it has taken for Rowling to do this. It’s easy to say ‘well, she’s got billions and a huge platform – what took her so long?’ but I think that’s unfair. With that fame comes pressure and scrutiny that the rest of us cannot imagine. By entering this arena, she is exposing herself to significant risks, volumes of criticism beyond anything most of humanity will ever experience. I applaud her.

Words matter, and with just a few words, JK Rowling has changed the gender debate for the better. The tide is turning, the waves are getting bigger. Thank you, JK.