There's a question I've been curious about for a very long time: if a gay man and a gay woman get married, would you still call that a "mixed orientation" marriage? Or might you just call it "doomed"? ;-)
Note in response to comments: despite my cheekiness and what many people do believe about them, I don't believe they're doomed and didn't intend for this post to be any kind of assault. See comments for more info and a link to a blog by such a couple.