to be interesting and sympathetic, and not to immediately pattern-match to a dystopia that kills everyone who doesn't look exactly alike.

One possibility is that a society that practiced genetics could actually make its population more diverse - a lot of modern human societies are really pretty homogeneous.

Such a society could also take steps to eliminate correlations between a person's superficial appearance and other abilities. For example, such a society could produce populations such that P(M|E) = P(M), where M="You win the Olympic Marathon" and E="You look like an Ethiopian".