Something that bothers me...
Maybe it's just the fact that the writers don't know what the crap they're doing, but it seems to me that there should actually be more women in the Imperium than men. A great deal of the men are conscripted into the Guard, or on certain planets killed off early in the attempts to find recruits for the Space Marines, or conscripted into the Skiitani, adopted into the Schola Progenium, or into the Arbites-- all of these organizations are depicted as mostly or entirely male in the fiction from what I can tell.
... and yet... somehow... most fiction that depicts civilians shows them as also mostly male (Dark Heresy, the Ciaphas Cain series, etc spring to mind). It doesn't really make much sense, apparently going by the fiction that there is Humanity in the year 40,000 is suffering from a shortage of women? Like out of every 100 citizen there's 30 females and 70 males? Personally I would think that this would mean there SHOULD be a disproportionate amount of women in the civilian population of worlds that are not entirely militarized (like Armageddon or Cadia), simply because of how many men they turn over to the Guard every year as tithes, and their own PDF as well which tend to be all-male in the depictions.
I know, thinking too deeply into science fiction (which itself is almost never internally consistent), but it always made me scratch my head at how stupid it seemed.