(collated and expanded from twitter because I feel this should be saved somewhere)
Having a think on stories that question gender roles. There’s two tactics: one is to define different ones: frequently inverting the existing ones, i.e. women fight! men take care of babies! The other is to have societies where gender divisions are much less sharp, or non existent (or where gender itself is fluid).
They both have their attendant issues: inverting roles, I feel, just reinforces the notion that the gender divide exists. Though you can push this to absurd limits; or hope that flip makes people question assumptions, I worry that it simply doesn’t work that way, and that people simply think: “oh, same things, except we’ve inverted roles!” Different roles with the same boundaries just keep boundaries in place: if you’re saying, for instance, “look, in this book women are warriors/cool badass assassins/magicians and they’re the heroes”, you’re unconsciously (or less unconsciously) reinforcing the stereotype that only fighting is worth writing about: i.e. in our world what matters are “male” coded values, and you’re effectively saying that a woman is only worth talking about if she behaves like a man. It’s subtle (or not so subtle), but in our societies you can see it in the value we put on work: women who work (and thus do “traditional male” stuff) have more value than women who stay at home and raise babies (and thus do “traditional female” stuff). 
Also, when inverting roles, one can easily invert clichés rather than actual gender roles. See; women don’t fight! Of course they do. Of course they’ve always fought (see Kameron Hurley’s brilliant takedown), and history erases that because it’s written a certain way.
(and let’s not even get into different cultures having different gender expectations: for instance, Confucian society frowns on men fighting because it thinks that it’s puerile and that the true value is being learned. Though there tends to be a constant in all societies that raising children is not really work at all *sigh*).
The approach with less sharp/non-existent gender divisions (which includes fluid gender and non-binary gendered people who aren’t gender fluid) is more difficult, and runs the risk of presenting an idealistic society, and erasing stuff that goes on. No gender prejudice at all in the future, for instance, though I hope we do get there eventually, feels very far off in the sense that history has shown that we’re very good and very sneaky at maintaining prejudice.
All in all though, would rather plump for less sharp gender divisions? Call me idealistic but I want a future/an imagined society that’s pleasant, that speaks to me, and that has women/genderfluid people doing all sort of kickass things without gender divisions (and men doing the kickass things they want too, whether that is raising babies, crying or having typically “female” coded behaviours). In House of Shattered Wings, I tried very hard to have little gender prejudice and few gender roles: the soldiers in the war are indifferently male or female, and same with the heads of Houses, who are split half and half, roughly. Arguably the most ruthless and talented head of House is Claire, who’s a woman (the others have a definite tendency for over-confidence and schemes that blow up in their faces).
ETA: about having completely different genders (invented ones that are neither male nor female), something I haven’t tackled here: I feel it can work, but that it’s tricky to do well? If you don’t differentiate your genders enough from the existing ones, people will still fall back to the existing gender boundaries? (and also, of course, it still presents a society with sharply defined gender boundaries, which reinforces the notion of “proper” gender roles, which I’m personally not a fan of).
Yeah, I know, this isn’t really a post. More like me working out things, and I feel like there’s tons of other things that really need to be said on the subject! I would love to hear other people’s take on this?
 While, of course, not being worth as much as men. Because.