I shared my personal take on all this as a 'mixed race' person myself on the 'Garvey vs. Selassie' thread.
Now about this statement from Adam: it assumes that the goal of 'breaking down racism' is changing individual white attitudes. That's not really my goal. I mean if racist whites want to change their attitudes then great, but personally I couldn't care less what their attitudes are as long as THEY HAVE NO POWER TO ENFORCE THOSE ATTITUDES ON ME. In other words, crackers are free to sit around in their log cabins in Kentucky or their luxury apartments in Manhattan and mumble into their whiskey-soaked beards about how much they hate Black and brown people, matters not a whit to me, what matters is that they can come and attach me to a chain and drag me from a moving truck to my death (in the Kentucky log cabin case) or order their slavering-at-the-mouth police lackeys to shoot me in the back (in the Manhattan penthouse case). Once they no longer have the power to do these things (in other words, once Black people are strong and organized enough to make it a lot more trouble to them than its worth to try to do these things) that's breaking down racism to me.
Not to say it wouldn't be great if white racists changed their personal opinions and decided to love all humanity and give out hula hoops and candy in the ghetto, but its not my priority.
You know I once came into contact with a guy who was a former Nazi skinhead who claimed to have made this great turnaround in attitude for the exact reason you're talking about, the arrival of a 'mixed race' relative. A white 'jewish' friend of mine (anti-zionist in case you're wondering, I don't hang with zionists) confided in me that he'd been talking to her and said about his past "but don't get me wrong, I never really hated Jewish people, cos you're white". Makes you wonder how much he had really changed. (If I'd hung around the creepy bstrd for longer, he'd probably have told me he never hated Black people, only Jews.)