[Major Tom]

I think that there is enough cultural paranioa in just about every society to keep 'the cultures separate'. Look in any society, and 'intermixing' is looked down upon, even in very liberal societies. You can force equality in law, but never force it in thought, unless some brainwashing machine is used, and that would require a lot of quarters.

(on a side note here, I never understood why different types of people are called different 'races', as you do not call a poodle to be of a different race then a schnauzer. Indeed, isn't there just one race of humans? The Human race?)