The Beggars Trilogy by Nancy Kress touches on this as well, but is more focused on the issues with superintelligence rather than just gene alteration, although, because people are vain, the preference for things like hair, skin and symmetry also exist in the story’s world. Oh yeah, and the coolest concept from this trilogy is a thing called “sleeplessness”, where people can alter there genes to remove the biological need to sleep, allowing people to be able to be productive for as many hours as they desire.