Comment by ineptech

The problem is that some racial bonuses are things that can be plausibly explained away by background (stat bonuses, mental abilities, humans getting a feat) but a lot aren't (aarakocra flight, dragonborn breath weapons, halflings being able to hide more easily), and they're all balanced against each other. Does an aarakocra raised by humans get human bonuses, and still get to fly? Does a human raised by aarakocra lose their human bonuses but grow wings?