Why are we born Han? How can we determine which nationality we are?

Just like all the large ethnic groups in the world (Han, American, Bangladeshi, Russian, Japanese, Brazilian and Indian), the Han nationality is also a huge ethnic melting pot. Many ethnic groups have merged into the Han nationality in its 2,-year development history, and now many compound surnames are from ethnic minorities who have merged into the Han nationality in ancient times.

So there is no standard of blood and gene to determine what nationality a person is. If your parents are Han nationality, you naturally inherit the blood of Han nationality.