I'm always intrigued by the chemical ingredients of interracial attraction. This extract from a novel I've been reading fervently was particularly interesting:

"I didn't realise it at first, but I also felt threatened by black women: this was jealousy. A sex-love existed  between white men and black women. This was an old love, as old as the hills around me. For centuries, white men had spread their seed as they pleased, had taken as many of their slave concubines to their beds as they could: blacks, mulattos, women with skin the colour of coffee, cinnamon, muscovado sugar; women the colour of mahogany, so black they were purple. This habit hadn't ceased. The white man still strutted, still behaved as father, oversser: the white man, I suspected, carried a deep carnal longing for the black woman. I saw it, smelled it, felt it, even understood it. But I couldn't compete. And what, just what did black women think of the white man's attentions? What did they say behind his back? I dreaded to think."

Monique Roffey, The White Woman on the Green Bicycle