Board Thread:Warhammer 40k General Discussion/@comment-7699236-20150618150629/@comment-6078851-20150622150029

i agree with sanguiniuslives that female astartes could be relatively easily incorporated into 40k. emps had a ton of secret projects, so who's to say he didn't start a female primarch project, but for whatevever reason it was put on ice, cancelled, or didn't work... or there could be a fully functional female primarch under the imperial palace just waiting to be found and released from stasis.

we all agree that as things stand male astartes gene seed will not work to create female astartes, regardless of how much genetic know-how is applied to 'port' it into the female genome. but if a female primarch (either adult, child or embryo) were introduced to the lore as a discovery of one of emps' unknown projects, then her gene seed could be used to create fully functional female astartes.

personally i would like to see a chapter of female astartes led by a female primarch (although not in person, that would be terrifying :P)  sisters of battle are admitedly kick-ass, but despite the fact that they wear power armour and use some astartes weapons they are still 100% human and they don't fill the role of female astartes.