I'm not really for her but Ann Coulter made a really good point about this in her book. She was basically saying that a lot of biracial entertainers pick and choose when they're black depending on when it helps them.

Mariah didn't publicly acknowledge that she was biracial until the mid 90s when she realized she needed Diddy's help to seem hip and credible to the black community and Halle Berry was than happy to claim the Oscar even though her black father walked out on her and was raised by her white mother.

http://www.youtube.com/watch?v=nR5hLJeGl3Y