Taboo? Like, half or more of the NPCs in the game that deal with romance at all, that romance is with other races... Longhaft (Hyur) and his ladies (Miqo'te), Yellow Moon (Roegadyn) and her fanboys (assorted), Severian (Hyur) and his lost love (Miqo'te), Thancred (Hyur) and the ladies he flirts with (assorted), Moenbryda (Roegadyn) and her merciless teasing of Urianger (Elezen) - just a few examples. In none of these is it even slightly implied that there's a mixed-race taboo.
If a mixed-race taboo is the official excuse they're going with, they're sure doing a piss-poor job of illustrating it in-game!
Much simpler, I think, to stick with a rule like, "The child is always the same race as the mother, regardless of the race of the father."
