I found that going into a long discussion of genetics and backgrounds and hair colors and eye colors and "isn't it interesting?" tends to get people to, um, stop talking about it.
I mean, it IS interesting to me, but I'm quite sure people who make little blippy comments didn't intend to give up 5-10 minutes of their time to hear a dissertation on genotypes.
But that's when I get the questions. The questions when it's just me and DS aren't nasty. They can tell he looks a little different from me, that he's something a bit more than caucasian. He is pale but gets golden, he has almond-ish shaped eyes that are amber in color (the only other way to describe their color is to say they match his hair, which they do, but his hair is RED and you can't say "red eyes", can you?), and he has red hair that can go from reddish brown to bronze to copper to strawberry blond depending on the light.
When hubby gets the questions the questions aren't pretty, and he's usually so taken aback that he can't say anything, he just stares. The worst by far was when DS was an infant. DS was very pink, had blue eyes, bright bright ORANGE hair (seriously, orange, not red, just orange), and didn't look even a bit Korean (he's a quarter), let alone the Portuguese hubby also is (1/4 that 1/4 Welsh, 1/2 Korean).
Hubby was standing outside a Sears or JC Penney women's dressing room. Holding diaper bag, baby in baby sling, woman's purse, and just waiting.
Woman came up out of the blue and declared "it looks as though you STOLE that child!!!"
Not really sure that anything said or not said to that woman could cure her from thinking things like that, and in fact I'm not sure hubby managed to get anything out of his mouth before she walked away...
But the long discussion of genetics and how both sides have red hair hiding in them and his cousins with matching backgrounds (their dad was white like me) look more Korean than their mom or uncle BUT they also have the amber eyes, and blah blah blah blah blah...has worked for me.