Board Thread:Warhammer 40k General Discussion/@comment-6078851-20130130174042/@comment-1713318-20130318080230

You're missing the point: the Emperor never had a mother in the sense that he never had someone he could connect with sentimentally. Yes he was physically born out of a woman's womb, but he had been profoundly changed by the raw power invested in his foetal body before his birth, and the moment he gained access to the collective power and experience of the sum of beings that he had become, he simply no longer had anything in common with his earthly parents.

I'd add that most Primarchs had a measure of the same problem: since they matured so quickly, and were so superior to their earthly parents, most of those that had "normal" parents had somer trouble connecting with them and their people. The only ones to be close, really close to their people were Vulkan and Angron, the others ended up as savior-like messiahs to their people. (And then you had special cases like Mortarion and Night Haunter which were even worse!)