This immediately scuttled Wong's chances, because the characters of O-Lan and Wang were married, and under the Hays Code, showing race-mixing on-screen was tantamount to jizzing on a burning American flag. So a Chinese-American woman was denied a Chinese role because she would have been pretend-married to a white man, even though he was caked in all the yellowface makeup that the World War II propaganda department could spare. You know, to protect America's moral fiber. So the role of O-Lan instead went to Luise Rainer ...
In Chinese, "Luise Rainer" means "Thieving White Girl."
... who was born in goddamn Dusseldorf. And of course she won the Academy Award for Best Actress for her grounded, realistic, and sensitive portrayal. As a consolation prize, Wong was instead offered the role of Lotus, a concubine who serves as the story's sleazy villain. She declined, and responded, "[Y]ou're asking me -- with Chinese blood -- to do the only unsympathetic role in the picture, featuring an all-American cast portraying Chinese characters." That's a very polite way of saying, "If you want me to betray my culture, get another white girl to do it."