Board Thread:Warhammer 40k General Discussion/@comment-69.143.134.163-20150419161351/@comment-8881468-20150703221236

109.204.164.166 wrote: My theory is that "lost Primarchs" are both girls... The macho-yber-god-of-a-man could not tolerate a female progeny, instead they became base genetics for "imperial assasins" and "sisters of battle"

./at0miclich (male but thinking why we all these kickass females in canon...)

fascinating, however, as previouisly stated in Scars Malcador says that he wanted emps to create female primarchs, which he did not do..

2nd problem: Sisters of battle are regular humans and the officio assasinorum people are also implanted differently from astartes.