Ok at the risk of starting a flame war, in all seriousness i'm curious as to why we don't see much, in relation to quantity of written text, in reference to the women of the 41st millennium. Now this could obviously be for a couple of reasons (lets exclude all assumptions of male dominance and chauvinism, k?) that i can think of at least,
1) in general history shows us that there are mostly universal cultural tendencies to refer to the collection of humanity as masculine (i.e. mankind, man, etc) or gender neutral (i.e. humanity, humankind, etc.). Rarely are we or people referred to en mass as feminine. So we could conclude from this that when all the human inhabitants of the 41st millennium are referenced as a whole or large group, they are simply being referenced in general and masculine. Now this presents some issues to resolve if this is the case:
a) This idea fits when referring to the whole or groups at large, however it does little to answer the individual characters we see in the collected writings are all male, as are the armed forces seen in the stories.
b)This idea also gives tremendous credit to the creators and writers of 40K works in their creative planning and execution through numerous different publication sources in developing a cohesive logic behind even the expressions of the created world. And i find that highly unlikely considering the contradictions we've seen in numerous places.
2)Another reason the prevalence of male gender inhabitants could be that in the list of stories, fiction, tales, movies, and whatnot most heroes are male. Mind you before you go crazy about the long list of female heroes out there, lets be honest and admit that the list for male and female protagonist hero characters in all of literature and film (especially scifi and fantasy) don't come close to matching each other in length. Ok i can buy this idea to some degree, now where's the problem here?
a) This can account for the protagonists in our stories, however it does nothing to address the mass of males that make up the entire Space Marine Legion, the collective military of the Imperial Guard, and such.
The only concentrated evidence we have of 41st millennial women are the battle sisters, and they can even be seen as an extremest group by some in relation to the entire imperial culture. So the question is where are all the ladies? Ok i can buy that they aren't written by male authors often in general anyway and much less in a grim dark future of 40k, however they should at least show up in the social structures right? We have a theoretically integrated military force here in the US, so shouldn't there be women in the IG? There are some written examples of planetary defense forces or Arbites as women but i can only think on a couple.
If cultural lines of 40k are so grayed bc of violence that race is looked at based on what "unsociable and excessively violent world" you were recruited from, no longer on simple race (and this is a necessity when writing on a large scale that covers galaxy, things have to get smaller), then it seems that gender would also be grayed as well. That being assumed (and that women aren't being protected as "breeders" which there is no evidence for -thank God) then it's only natural to assume that women would be members of the military forces through out all the Imperium, right?
So there should be a female element to military forces. And it would be significant in number if the ratios of male to female hold true still in the 41st millennium. All things considered if we are talking deployed forces of military on the scale of millions in one conflict, then everyone who could hold a weapon would be recruited, in times of crisis anything goes, so women would be inducted and recruited just like men. (Again unless some sort of "save women" plan was put into effect, which there is no evidence to.) So at least a quarter on the conservative side should be women.
This would go beyond the IG, Arbites, and Planetary defense forces. The Battle Sisters excluded from this discussion bc in comparison to the masses of other military forces out there, their number is far too low to be the "Oh all the women are Sisters" answer. And this does bring reasonable question (No flaming please!!) then to why are all space marines male? They are implanted with the gene-seed so it can't be that they are genetic clones of the emperor. In theory only the primarchs have any legitimate reason to be male. So if a woman could make the cut to become a space marine, and i'm sure in all this time at least one could have, then where is she?
Now keep in mind that all of these thoughts require that we take into consideration we are talking about a fictional world that is being detailed to us by writers. As one who is working on his own first full novel, i came into realization that when describing the fantastic or a different culture than any we know, we are limited by our understanding of the real and tangible world around us, and therefore can only use the things we know to describe the fantastical. The same experience is encountered frequently in theological studies. We try and define the infinite in tangible and finite terms. So we automattically limit some of our abiility to describe things adequately...but that's almost beginning to sound like a tangent...so point being as a writer you are required to either describe things so your reader can understand it using words they are familiar with (which can sometimes leave moments that don't quite fit in the realm of your story) or to create something new and then have to explain to the reader what that new something means and help them understand it in light of the fictional world. Hence the possible simplification of people to the male gender.
Please if it's possible as far as you are concerned this is a legitimate question i'm curious about and am not interested in flaming or trolls, though i do feed one occasionally that lives under a bridge near my apartment, but it's a nice troll. He only gets cranky when he's hungry, and i can relate, that whole blood sugar thing and get ya if you're not looking...so if you can't write something nice, just shout at your computer screen...thanks.