Why not make a female inquisitor leading the squad of Marines?
With all of the genetic implants given to marines, I'm pretty sure they'd have figured out whether there was a woman in their order or not.
Besides, whose to say there isn't a chapter of all female space marines out there? Just because they haven't made models for them doesn't mean they don't exist. Armies pop up in the game that never existed before pretty regularly and everyone easily accepts those as cannon. Why not, a little known all female space marine chapter?
You think sisters of battle have have the only female access to power armor?
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), but what's so bad about Squats? I know that they practically wrote them out of the background, but were they ever important enough that their (non-)existence changes the setting in any big way?