A study by the Chinese Academy of Sciences into the gene frequency data of Han subpopulations and ethnic minorities in China, showed that Han subpopulations in different regions are also genetically close to the local ethnic minorities, and it means that in many cases blood of ethnic minorities has mixed into Han, while at the same time, blood of Han also has mixed into the local ethnicities.
For decades following the Chinese Revolution of 1949, marriages between laowai (foreigners) and Chinese were unusual and perhaps even nonexistent during the Cultural Revolution, but they were never explicitly banned or judged unacceptable on a racial basis. It was only in the mid-1970s that the first petitions for permission to marry foreigners were accepted, with the thawing of diplomatic ties between China and the United States. Such marriages remained relatively unusual for a further two decades.
From 1994 to 2008, each year has seen about 3,000 more mixed-race marriages in Shanghai than the previous year. That has caused a major shift in China's attitudes to race and of Chinese children of mixed race heritage because of globalization.
^Du, R; Xiao, C; Cavalli-Sforza, LL (1997). "Genetic distances between Chinese populations calculated on gene frequencies of 38 loci". Science China Life Sciences. 40 (6): 613–21. PMID18726285. doi:10.1007/BF02882691.