1) Dr. He did not cause evolution. By definition, it's a change in allelle frequency over time. He only was able to change the alelles of two people at once. Populations can evolve, but individual people cannot evolve.
2) What he did start was a basis for natural selection. No other person has the edited CCR5 gene except for those 2 Chinese twins, which is a heritable variation. It also increases the biological fitness of the species, as less of the population will die from the disease.
3) Yes it should be permitted. It helps increase our biological fitness. From what I've read, it is not damaging to other functions of the human body, which means that all he is doing is preventing the ability to contract a deadly disease.
