Board Thread:Warhammer 40k General Discussion/@comment-7699236-20150618150629/@comment-26516936-20150621030230

In one of the Horus Heresy Books - I think I was Deliverence lost - Malcador is talking with one of the loyal primarchs and mentions that he had urged the Emperor to make the primarchs some sisters but the Emperor decided against it. This suggests that creating a female primarch & thusly female astartes was well within the Emperor's capabilities but he decided to stick with males largely because he wanted warriors & being a pretty patriarchal type didn't see women as effective as warriors as men.

There is one rather intriguing possibility though, in that the Emperor created one primarch - Lion el'Jonson - and used him as the prototype for the others & did the same with the astartes, creating the Dark Angels first & used them as the prototype. Now here's the intriguing possibility, what if the Emperor did create a female primarch at the same time he created the Lion but decided only after that to have only sons. The Emperor wouldn't have destroyed the female primarch embryo as creating them involved far to much effort & resources to waste, he would have frozen the embryo in cryo & stored it someplace safe, perhaps in a separate vault in the secret lab that Corax entered to get the genetic material he intended to use to rebuild the Raven Guard. If that indeed happened than there might be a female primarch embryo hidden somewhere just waiting to be gestated & born. Or even better perhaps the embryo has already been secretly brought to term & there is a female primarch hidden somewhere in the galaxy learning & growing into her power.

What that means is there is nothing really stopping the creators of Warhammer 40k from introducing a female primarch into the mix, indeed such an addition would add a wonderfully unpredictable element to the story. In fact the female primarch could act as the harbinger to the return of the surviving loyal sons & be the Emperor's secret ace in the hole for the coming confrontation with chaos in the upcoming 40k end times event.