That's a howler.
Like I say, the normal English term for mutation is "birth defect". Have you ever heard anybody talking about "birth enhancements", as in "My little Suzy is making straight A's in school because of that birth enhancement" (i.e. because of some supposedly beneficial mutation like being born with two heads), and supposing also that two heads are better than one for taking tests in school?
For that matter, have you ever had the ladies from the Mothers' March of Dimes come to your door asking for money for research to CAUSE mutations? My own experience has been that they're always asking for money for research to prevent them.
Your thinking of mutations as in X-men or chernobyl, not mutations in the sense of genetics.
We are not concerned with the 'normal English' definition, but the scientific definition. The scientific definition includes mutations of germ cells brought on by radiation, chemical damage and even random photon collisions, but applies primarily to replication errors during meiosis. Birth defects also include errors during ontogensis which are brought about by damage to non-germ cells by radiation, chemicals or some other errors while in the womb.
Mutation as far as evolution is concerned only applies to changes in gametes. Birth defects can be caused by factors not related to evolution. That is why 'birth defects' can not be used when speaking of evolution.
Science 101: The human genome is rather plastic over generations. Genes that are beneficial allow that individual to breed and propogate the gene.
An extreme example is the sickle cell hemogoblin gene. No doubt you are aware of sickle cell disease and its sad consequences for those afflicted. Is this gene a curse from God? Of course not. Individuals who carry only one sickle cell gene (heterozygous) have an advantage over those who have no sickle cell gene. The heterozygous sickle cell gene is protective against malaria. Hence many people from malaria endemic regions e.g. Africa carry the sickle cell gene. They live to adulthood and proprogate their genes to future generations. Those unfortunate individuals who have two sickle cell genes (homozygous) die. Assuming four children: statistically one will be homozygous with sickle cell and die, one is homozygous without sickle cell and may die from malaria but two are heterozygous and will likely live to adulthood and propogate their genes.
Evolution is not complicated and it's occuring everyday on this planet.