Creationists insist that mutations are very rare and are usually, if not always harmful. But the fact is that the vast majority of mutations are completely neutral. They'd have to be because, according to the National Center for Biotechnology Information, there is an overall average of 128 mutations per human zygote! So apparently, in creationist terms, very rare means more than a hundred per person right from the point of conception. Because those are just the mutations we start out with. Our cells will mutate again 30 more times over the course of our lives, and some of these subsequent mutations can be passed on to our children too –usually with no more effect than those we recognize as family traits.
"8th Foundational Falsehood of Creationism", Youtube (March 22, 2008) - Foundational Falsehoods of Creationism