Funny part is: mutations happen to individuals. And they don't spread to populations if the individual can't reproduce. But we're too thick to figure that out...
Even more amusing is 150 years later, thousands of scientists, hundreds of textbooks, millions of papers and nobody ever thought that sterile mutants cant breed! Your awful smart to have caught that one.
It can get pretty funky when you bring up an issue that they know for dead certain kills their fantasy.
Its over now. With something so incredibly subtle as what you have just suggested finally coming to light... its implications are stunning.