Do you think that attraction to "exotic" looking people, in what ever way you define that, is an evolutionary adaptation for diversifying the gene pool? Is it a biologically stimulated reaction, beyond free-will control, that trumps cultural affinity or other "nurture" arguments and attracts us to those of a different background than ourselves? In other words, do I want to bang hotties because we'll have sexy looking children?
I think so.
The flip side of this is to cite the whole Oedipus argument, where men marry women like their respective mothers. In this case, the gene pool isn't diversifying at all-- it's an intelligent and humorous lady who can take tequila shots down like it was "waw-tah".
But, I feel that exposure to the "exotic" is a modern phenomenon, and furthermore, it is only within the past 20 years or so that it would even be socially acceptable to intermingle with one considered "exotic". (And I am taking a way liberal view on this topic here, for simplicity sake. Unfortunately, a sizable [again, I'm being generous] part of the global population still ignorantly talk of "race" and "staying with your own kind".) The Oedipus argument is moot because the alternatives were minimal. Today, we are free to go beyond the familiar.
Sexual freedom has exposed repressed evolutionary biases! Thanks Hippies!