J.K. Rowling on Thursday backed a British woman who lost her job for tweeting that people cannot alter their biological sex after she lost a legal case against her employer. Maya Forstater was sacked from the Centre for Global Development, an international think-tank, after tweeting her opposition to a British government proposal that would make it easier for transgender people to change their legal sex. Some colleagues raised concerns that the tweets were transphobic, a charge Forstater rejected. She has said she supports everyone’s human rights but maintains that it is not possible to change sex. On Wednesday, an employment tribunal rejected her claim that she had been discriminated against for her beliefs and ruled that her sacking was lawful, sparking a response from the “Harry Potter” author. “Dress however you please. Call yourself whatever you like. Sleep with any consenting adult who’ll have you. Live your best life in peace and security,” Rowling tweeted.