Board Thread:Off Topic/@comment-26397825-20160524033118/@comment-24534644-20160528230012

A child of a human/faunus, who is themself human, would indeed be physically indistinguishable from a human with both human parents. The only way someone would know is if the person were to make it public knowledge that they're the child of a faunus, or if they met the parent in question and saw they they were a faunus.

Still, it's easy for me to imagine there being those particularly racist folks out there who'd see having a drop of faunus blood in them (or as Phantom says, dormant genes) as being "all-faunus". That's how half-black-half-white children were viewed by full white people, back in the day. It's much less obvious, but once a person finds out, that's where the question comes into play.