You have problems eating thinking of "`races` mixing" ?
What about this: the entire humanity is, that is all specimen, including yourself, is the outcome of in and outbreeding between countless ethnies, groups of different skin colors, cultures and even religion/folklore followers.
If you have a digesting problem with this, we may just call it nature but your comment is what could put many not at ease. That being said, I would at least guess we agree on the ruling that it gets us closer to nature and some commonly accepted ethic with regards to human life and procreation.