Thread:Nmtan/@comment-5354013-20130910215139/@comment-10760902-20130918010555

The result's ratio is fixed. To know which monster will be 70 and which will be 30, I think first is compare the rarity, then compare the breeding time. The rarer (longer breeding time) will have the less chance in output.

This is my speculation depending on the results (me mostly and from friends), so I can only explain it statistically, since all the algorithm code are server-side.