What happens if a non-human has a kid with a tiefling?

@SnappyErikaWhat happens if a non-human has a kid with a tiefling? Are there halfling tieflings distinguishable from normal tieflings? I don't think they can have kids with non-humans. otherwise, I'd say kid is a tiefling – magic of bloodline overrides genetics

— (((Mike Mearls))) (@mikemearls) June 30, 2016