Also, a theory is never "proven" except in mathematics. It may become well established and semi-axiomatic, but it is never considered absolute and unquestionable.
You've never seen a genetic mutation that enhances one's reproductive advantage? Well, gee, how about blonde hair?
Also according to your post, blonde hair somehow enhances one's reproductive advantage? Again, on what do you base this assertion?
I'm hoping you were joking with this statement.