Many people condemn cosmetic surgery as superficial, yet most of us seek to improve our appearance with braces for our teeth, skin creams, and fashionable clothing. This chapter explores arguments for and against manipulating genes to aesthetically enhance our children. I focus on the problem of arms races that might lead each parent to act in ways that are collectively harmful (or counter-productive). I conclude that although such worries are well-founded, in most cases parents should be free to alter themselves or their children even for superficial traits, provided that in doing so they are not predictably reducing the well-being of their children.