[ahayes]

Can you read? Most of the time these are not genetic effects. Go back and reread my initial post.

[VxH]

>>Can you read? Most of the time these are not genetic effects.

 

    From your original Post:
        [Typically chimeras originate from two embryos fusing in the womb]

 

 

And why does this defect take place? 

 

Could it be because the mother has a defect in the DNA that codes for the enzymes involved in embryonic development?

 

Or maybe she has a defect in the DNA that recognizes and spontaneously aborts "birth defects".

 

Perfectly plausible hypothesis. 

 

Quack quack waddle waddle... Oh look, it's genetic.