I believe the mixed racial studies to be cloudy. They kinda make the numbers work in their favor a bit. Your kids are half black half white. They could all have children with 100 white or black partners. Those children would be 1/4 black or white depending on which way they went. Then if those children had kids with someone of their majority race, those children would be 1/8 black or white. But by that time they would simply look black or white and not remember that great grandma or grandpa were black or white. I believe this is a cycle that has already occurred a couple times. While the numbers will be multiplied based on societies acceptance compared to past generations, I think the study is a little off in a a that it tends to imply that people will be half/half or even just a "grey" people that holds all racial DNA. I find it interesting though to think of how different the world could be without racial hate or having a race card to pull. Not to hijack, but I recently did a little looking into it and wanted to get in on a the conversation.
As far as John Stewart goes, he is a little wishy washy for my taste.