According to the Sumerian texts the Anunnaki took an already existing primitive humanoid and blended their DNA with it.


They even hosted the fetus in their own womb and gave birth to us.


But Adamu and Tiamat / Adam and Eve could not procreate until Enki gave them the fruit of the Tree of Knowing.


The story goes that to give them the power of procreation Enki had to give adam and eve some of his life essence.


So Ninghizidda put all three of them to sleep and took the Rib of Enki and extracted the Life essence from it, then he inserted it into the rib of adam and eve.


After this surgery they were able to have Children on their own.

Like the 'gods'.