OK, because I’ve seen one too many %%% storylines about mixed-race people in fiction (expanded for SFF to include the children of humans and aliens/magical creatures, etc.). For your information:
We are not psychopaths, terminally maladjusted, forever torn between two cultures in a way that will inevitably destroy us. We are not freaks or hybrids or mongrels or circus animals, forever exhibited as examples of what can go wrong in human/alien/magical creatures relationships; neither are we featureless saints exhibited as examples of interracial/interspecies harmony.
We are not special, magical or possessed of numinous powers by virtue of our non-white/non-human blood; we are not the tamed Other, made acceptable by an infusion of white blood and white customs, the “safe” option with only a hint of fashionable exoticism and none of the raw difference of “true” foreigners. We are not a handy, non-scary substitute for diversity in fiction.
We do not have pick sides unilaterally. We do not have to share the identity of our mother or of our father to the exclusion of the other parent (and most of us will find it quite hard to completely reject one half of our heritage); and our parents are not perpetually locked in some cultural war in which there would only be a single winner. We can be raised with love and respect and in a meld between two cultures: we do not have to be orphaned/single-parent/neglected/abused to exist.
Our parents are normal beings, and so are we.
If you’re using mixed-race people in your fiction and feature ANY of those tropes, do please think for a moment of what it is that you’re saying (and I wish I could say it’s not the case, but I’ve seen all of these–yes, even the hybrid/mongrel–at some point in recent SFF, either in print or in other media).
ETA: also, in case you’re wondering? The use of the word “half-breed” to refer to mixed-race people is NOT acceptable in any context (except possibly as a slur in historicals). “Mongrel” should also be banned from your vocabulary on mixed-race people. I don’t particularly enjoy being compared to animals, or the long history of prejudice inherent in that term (it’s a bit like thinking “mulatto” or “nigger” are appropriate descriptive words). For God’s sake, think on what it is you are saying before flinging this kind of word around.
Disclaimer: this is based on my experience and on those of friends growing up (mostly in Europe, and most Asian-white mixed-race). I tend to think a lot of it applies elsewhere, though…