Early in college, Ou Jiayong had already learned two things. One, textbooks can be wrong. And two, it can be hard to change them — especially on topics as sensitive in China as homosexuality. In 2016, during her first year at South China Agricultural University in her hometown, Guangzhou, she stumbled across a psychology textbook that described being gay as a mental disorder. As a lesbian, Ou felt that was unacceptable, but the complaints she made went nowhere. So Ou, who also uses the name Xixi, brought a lawsuit demanding that the publisher remove the reference and publicly apologize. Her case has renewed the conversation about tolerance and human rights in a country where discrimination based on sexual orientation is rampant and where homosexuality has long been seen as incompatible with the traditional emphasis on marriage. In a letter to the judge, Ou, now 23, recalled being “deeply stung” when she read the textbook.