I feel that this only applies for the elite, especially when there's a lot of political infighting; marrying an outsider will weaken the whole family which is really bad in a low trust society but that's another topic. This is not true for all social levels of China. China has practiced for what my international affairs prof terms as "reverse genocide". What is it? When an ethnically Han Chinese man or woman marries a non-Han partner, their children and their whole family are considered Chinese. To be fair, there are exceptions since China (and you can argue most of Asia) is still somewhat racist. If your children do no look "Chinese", they will not be considered as chinese.