Cobramax76 said:
Well, the IG has thousands of regiments, that draws from worlds with different cultures. This leads to very different situations regarding the presence of women in the military. Some of IG regiments may be male-only (in a classical "men fight, women stay in the kitchen" chauvinist fashion), some may be gender-mixed (Cadia, I guess) and other may align both single-sex male or female units (so as to limit distractions among the troops). It's a very big Empire, after all.
My rule of thumb would be 'If you can think of it, then it exists somewhere in the Imperium'. It also applies to the Ecclesiarchy.