Wow, I had not realized that 'gender roles' inside of a randomized game atmosphere was such a contested topic. I saw this thread yesterday, and had to fight the urge then to respond with "Chill out."
Some of you have clearly over-thought this idea, and are actually taking offense at it. To be honest, based on some of the responses that I read on the first page, I'm surprised that nobody is arguing we should get rid of the generated gods because that forces religion onto you (the player).
It doesn't matter if sexual dimorphism exists: what matters is how a particular culture comes to be, and how it is repeatedly re-enforced with each following generation. We're talking about a universe where there's actual angels and demons, immortality, and walking corpses, and people too stupid to realize that their king is a vampire. Or a minotaur.
One of my recent dwarf civilizations actually worshiped a male god whose sphere was fertility, pregnancy, birth, torture, and death (and I think also misery, or some other intensely negative word -- anyway, I blame him for the necromancy tower I had). It would not have been a stretch of the imagination for worshipers of this god to be complete chauvinistic asshats. The reverse would have been true for an earlier gen'd world where I had a pantheon of females lording over traditionally 'masculine' ideas.
Anyway. Point is, IF such a feature were implemented in a way that felt realistic, predictable, and consistent within a given world, I would not mind having it. It might even be fun to one day have this be a part of deeper cross-civilization interactions: perhaps a 'Male-Centric Civ' will refuse to honor a treaty with 'Neutral Civ' because it doesn't like that they don't care about gender roles, or a female-dominated bandit group may react aggressively towards male adventurers (as opposed to female ones). Just ideas.
And if it's not implemented? Oh well.
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Re: Graknorke and specific clothing
I definitely think that an established fortress would care about what they're wearing. If you've got golden statues everywhere, you shouldn't be walking around in rags, right? I don't think micromanagement would be a big deal -- if there are no dresses for a gender that prefers dresses, then they'll just wear the next best thing, be that skirts or pants or loin clothes, and voice a complaint about it. Learning to manage this stuff is kinda up there with learning to manage how much food you have.