Board Thread:Warhammer 40k General Discussion/@comment-6078851-20130130174042/@comment-3258762-20130316154208

The Adeptus Custodes pre-date even the Thunder Warriors, the Primarchs came after the Custodes, which probably means the Custodes are a completely unique form of Super soldier, so to speak.

The argument you bring up about the Primarchs is exactly my point: It has to do with the mindset, not the genes. If a Primarch could be turned, beings so extremely intelligent as to see through most anything, there is no way a normal astartes can do it, especially not while in the realm of the Chaos Gods.

The Emperor had children, yes, but those are natural children, born of sperm. When creating an offspring like that, you are infusing a very small part of your gene-structure into a being which will then form on its own with the two parts it has been given as a blue-print. Blood, and organs, contain the full DNA of a being, and by having that introduced into you, you would then not get some genes from the Emperor, you would get ALL genes. You can affect how a child will be, but unless you go in and tailor the genetic code yourself (like the Emperor and his Primarchs) then you will only get something remotely alike what you might have planned it to be.