Can the genetic modification in babies be reversed?

Answer

Perhaps the question does not mean genetic modification, but gene therapy. The aim of gene therapy is to provide an individual with a hereditary disease with a new gene to replace the non-functioning gene. Gene therapy on fertilized human eggs is ethically rejected, but has been used successfully in mice. For example, gene therapy in humans can be done via white blood cells. Since the intent is to heal, whether this is a reversible process is irrelevant.