For a second there I thought you meant darwinian evolution.. I certainly hope that's not where evolution leads us. But one would consider that being not able to talk would select us out of the gene pool so my guess is that even though we stutter, some of us must have been pretty fucking sexy. To attempt to answer your question, I know of some students where I work who have selective mutism but don't have a stutter. I don't know if mutism is related. That being said, sometimes I wish I as a kid chose mutism, it would have solved a lot of bullying. Edit: at the time being, your post is sitting at zero upvotes. I don't condone downvoting an honest question.