This may be the circumstance in "billboard" advertising...but not necessarily true on television shows and such. It is more the norm for a white male to be hooked up with a black female in a TV show. I don't think it is a true reflection of real life culture...but dates back to the antiquated notion of censorship and what can and cannot be shown on TV...ie: two beds for couples, no belly button shots, no mixed race couples, etc..

We are rather slow in catching up with the times. We've just recently (the past 5 years or so) saw a woman in a bra, instead of the bra being over her clothing, in billboard ads and TV commercials. The powers that be (the bible thumping, moral majority) try and think for us...and in turn let us see what they think we are capable of handling. I'd say you have censhorship to thank for differentiating between black male/white female ads and any other mix that would reflect the true norm...because it's what THEY think is the most acceptable.

__________________
Minds are like parachutes. They only work when they are open.

~Thomas Dewar~