What genus we belong to is irrelevant, this is more to do with how we look.

You can't collectively judge a race that you cannot tell apart from your own. Like wise, if a subset of your race were to look different from you, you would feel compelled to generalize about them. That's human nature.

The reality is irrelevant. Fine, races don't exist, but they are perceived to exist, and the parent is concerned with how his children will be perceived.

Well, some alleles (genes) cluster among populations, and many people believe that statistically different genetic populations equates to different races. It's a widespread mistaken belief that has no scientific basis, because having different races requires 100% isolation of the populations. There are many horrible things that have happened in the world on the basis of this belief, and it irritates me when people propagate it, even if they aren't doing so maliciously.

Note that I realize now I may have been quoting him out of context about the physical differences, kind of hard to tell.

Okay, based on recent comment, apparently a total misunderstanding.

You seem to have misunderstood my scare quotes around the word "interracial." I've always been clear that there is one human race, no more, and we are all part of it.

I'm glad to hear that. Yes I did not understand about those scare quotes, nor the scare quotes around "mixed blood".

What could you say besides interracial? Interpopulational? Intercultural?