Okay, this is going to sound totally random, but it’s something I’ve noticed.
Among many other reasons I like Torchwood is that there are mixed couples…and nobody mentions it. In most American media, if there’s a black person and a white person and they’re a couple…then generally being a mixed couple is their reason for existing. That’s what drives the plot, or is used for comedy or drama or whatever.
With Torchwood, you’ve got Ianto and Lisa, and race has no factor whatsover in their relationship, as far as we can see. Then in Sleeper, you’ve got the white husband and black wife, and again, race doesn’t matter one iota to the plot.
Doctor who too, with Rose and Mickey, and both Donna’s fiance and eventual husband.
American media seems to try very hard to match people with someone the same color, unless it’s for the above reasons. Off the top of my head I can’t think of one show with a mixed-race couple that just happened to be there and it wasn’t pointed out.
Anyway, this is probably stupid, but it’s a thought that crossed my mind.