I have learned a lot since writing about gender laws here last week.

I’ve learned that if you ever want to flood your Twitter timeline with people arguing about something, writing an article about gender laws is a good way to do it.

I’ve learned that some people do indeed get very angry about this stuff, though not always the people you’d expect. The prickliest communication I had wasn’t from a Trans-Rights Activist or a Radical Feminist. It was from a parliamentarian. And overall, I’ve had nothing like the venom I’ve seen directed at other hacks who’ve written about this in similar ways; for some reason or another, people are less horrible to me about this than they are to Janice Turner and Helen Lewis.

I’ve learned that there are some brilliant, learned and compassionate people out there, who come at this from all angles. One (purely anecdotal) observation is that the diversity of opinions within the trans-gender population is not remotely reflected in the bit of this conversation most visible at Westminster. The trans community’s opinions are not as homogenous as some reporting and discussion suggest. So here’s a tip for hacks covering this: don’t just book Paris Lees or talk about Lilly Madigan. Ask Kristina Harrison what she thinks. Or Tara Hewitt. Or lots of other people. The same goes for the 'radical' feminist side of this: there’s more to it than Germaine Greer. (Though for some media outlets that really should know better, having any voice from that side of the conversation at all would be an improvement.)

Which brings me to the most politically pressing thing I’ve learned. Mumsnet is angry. And here’s something I already knew. When Mumsnet is angry, someone in politics is in trouble.

Now, I don’t know how many Spectator readers are also Mumsnetters, but those who aren’t might just assume that site is all middle-class mummies twittering about yoga and little Sophie’s Mandarin lessons. If so, they’d be wrong.

Mumsnet is fab and full of serious, interesting people talking about serious, interesting stuff. For an increasing number of them, that means gender recognition, self-defined gender and the implications (practical, social, political and philosophical) for women -- by which I mean, people who were born female.

And again, purely anecdotally, it seems to me that a lot of those people are seriously unhappy. They think that the sort of self-declared gender laws that may end up in force in the UK, as they have in other countries, will do nothing less than render the word 'woman' meaningless, with all that that implies for equality and freedom and, well, civilisation as we know it.

To paraphrase some common sentiments: you can’t become a woman, because womanhood is based on biology, socialisation and experience that only those born to it can know; if the law dictates that a man can attain womanhood simply by signing a few forms, womanhood becomes empty and women lose any standing in society. Indeed, the very notion of objective truth goes out the window. To quote the formidably eloquent Kristina Harrison, accepting that people can define their own gender without external check or scrutiny is 'to assert that subjective and unverifiable will subordinate objective biological sex as the pre-eminent cultural-legal category.'

This is an aspect of the gender debate I avoided last week because a) it’s endlessly complicated; b) I’m wary of getting into questions about experiences and feelings that I haven’t had and can’t share; and c) I’d end up revealing that I never really understood the post-modernism texts I pretended to read for my degree.

So I’m going to stick to the mundane politics of Mumsnet’s epistemological essentialism. Some important voters are angry, and a lot of them are angry at Labour.

Partly that’s because some of them are Labour people and they feel let down by their own party. For all the caricature of Corbynistas being twenty-something men angry at their middle-class parents, much of the Corbyn surge in Labour membership has come from older women, some of whom have rejoined the party after years away. Labour women made Corbyn; could they yet unmake him?

Partly it’s because Labour is the party pushing hardest towards self-ID in gender. Jeremy Corbyn talks like a man who wants rules that allow someone to define their own gender. That would mean that the party’s all-women shortlists (AWS) would be open to someone who was born male, retained male physiology and had undertaken no action to change that physiology, and was legally recognised as male. Such a person would be eligible for an AWS purely because that person declared themself to a be a woman.

This, for now, is the hottest political flashpoint in the gender debate. And if you read Mumsnet, it could be the spark that ignites a full-blown political firestorm, where women abandon Labour in droves. Mumsnetters are girding for war and have armed themselves with a hashtag: #labourlosingwomen, a banner that also covers concerns about the Corbyn leadership’s somewhat macho attitude to the treatment of Labour women who don’t worship St Jeremy and the way allegations of sexual wrongdoing by some Corbyn allies have been handled.

Does this matter? Isn’t this just some online grumbling in an angry echo-chamber? Maybe, but some Mumsnetters scent blood. YouGov’s regular tracker on 28-29 January put Labour on 42 percent overall and 46 percent among women. The latest tracker, conducted last week, has Labour on 39 percent overall, 4 points behind the Tories, and down to 40 percent among women.

Has Mr Corbyn really lost 6 points of female support (close to 1 million votes) in a few days? Almost certainly not; these are just two polls and nowhere near enough to call this a trend. But could Labour’s stance on trans and gender issues alienate women in significant numbers? I think it cannot be ruled out.

Sometimes in politics, perception matters more than reality. Narratives matter, and the narrative of 'women vs Corbyn' could quite easily take hold, and become self-fulfilling. The gender wars are currently a niche interest, but if this debate goes mainstream (and Britain’s slide into identity politics and culture war suggests it will), there is surely at least the potential for a lot of women to start thinking very hard about the implications of Labour’s approach.

In short, all the necessary components are in place for a real political grudge-match, the sort of no-holds-barred ultimate fighting cage-match that aficionados of political combat will tell their grandchildren about.

Ladies and gentlemen, take your seats, grab your popcorn and let’s get ready to rumble. Because it’s showtime: Corbynistas vs Mumsnetters. May the best women win.