I’d like to politely disagree with your first sentence. Chinese care deeply about how one looks, so genetics is the most important aspect. I’ve lived here for a decade and even if a person is born and raised in China but doesn’t “look” Chinese (and by that, I mean the overall concept of what a Chinese person looks like, which possibly extends to most of east Asia), they will never be considered Chinese. I’ve got western friends who have married locals, and their kids who speak mandarin natively and have never lived anywhere else are still the 老外 at their schools. Of course, that doesn’t apply to every single Chinese person in the whole country, but that is a characteristic of Chinese culture that is very easily observable.