Bullying is AFAIK based on perceived weakness, being a good victim candidate. Granted, being "weird" and thus seen as not having many allies, easy to single out, is a perceived weakness. Still I would probably tackle the problem by other means (like convincing ginger kids to always protect each other). Deafness is clearly a defect, I don't really care about the deaf hamstering about how it is a culture. It is a culture made to deal with a defect, and as such it is a very respectable one, but it is just like the culture of grieving, if we become immortal we will not miss spectacular tombstones.
But sure on the meta level I do agree not all people will agree with me here. But there is an obvious solution of leaving the corner cases to the parents jurisdiction.
What I would want to avoid is arms races really. Such as in height (being important for the sex appeal of men).
I previously wrote a post hypothesizing that inter-group conflict is more common when most humans belong to readily identifiable, discrete factions.
This seems relevant to the recent human gene editing advance. Full human gene editing capability probably won't come soon, but this got me thinking anyway. Consider the following two scenarios:
1. Designer babies become socially acceptable and widespread some time in the near future. Because our knowledge of the human genome is still maturing, they initially aren't that much different than regular humans. As our knowledge matures, they get better and better. Fortunately, there's a large population of "semi-enhanced" humans from the early days of designer babies to keep the peace between the "fully enhanced" and "not at all enhanced" factions.
2. Designer babies are considered socially unacceptable in many parts of the world. Meanwhile, the technology needed to produce them continues to advance. At a certain point people start having them anyway. By this point the technology has advanced to the point where designer babies clearly outclass regular babies at everything, and there's a schism between "fully enhanced" and "not at all enhanced" humans.
Of course, there's another scenario where designer babies just never become widespread. But that seems like an unstable equilibrium given the 100+ sovereign countries in the world, each with their own set of laws, and the desire of parents everywhere to give birth to the best kids possible.
We already see tons of drama related to the current inequalities between individuals, especially inequality that's allegedly genetic in origin. Designer babies might shape up to be the greatest internet flame war of this century. This flame war could spill over in to real world violence. But since one of the parties has not arrived to the flame war yet, maybe we can prepare.
One way to prepare might be differential technological development. In particular, maybe it's possible to decrease the cost of gene editing/selection technologies while retarding advances in our knowledge of which genes contribute to intelligence. This could allow designer baby technology to become socially acceptable and widespread before "fully enhanced" humans were possible. Just as with emulations, a slow societal transition seems preferable to a fast one.
Other ideas (edit: speculative!): extend the benefits of designer babies to everyone for free regardless of their social class. Push for mandatory birth control technology so unwanted and therefore unenhanced babies are no longer a thing. (Imagine how lousy it would be to be born as an unwanted child in a world where everyone was enhanced except you.) Require designer babies to possess genes for compassion, benevolence, and reflectiveness by law, and try to discover those genes before we discover genes for intelligence. (Edit: leaning towards reflectiveness being the most important of these.) (Researching the genetic basis of psychopathy to prevent enhanced psychopaths also seems like a good idea... although I guess this would also create the knowledge necessary to deliberately create psychopaths?) Regulate the modification of genes like height if game theory suggests allowing arbitrary modifications to them would be a bad idea.
I don't know very much about the details of these technologies, and I'm open to radically revising my views if I'm missing something important. Please tell me if there's anything I got wrong in the comments.