When Emma made the romantic lead in
War for the Oaks a black man, it didn't seem like a big deal because we were total Delany and Sturgeon fans: we knew interracial romance—meaning human interracial romance, not Space Princess romance involving white men and green or red women—had been written by the time we were teenagers, which meant it was ancient history.
But now I'm wondering how common it was. My google fu is weak; I keep thinking some genre historian must've made a list of interracial f&sf romance stories, but I'm not finding any.
The lead in
Starship Troopers is
a black South American Filipino*, but I can't remember if there's even a romance in that book. If I had to bet money, I would guess Sturgeon got to interracial romance first.
* Thanks to Anonymous in comments for correcting that.