Rowling explains that she became interested in trans issues while researching a character she’s writing. She took her case to an employment tribunal, asking the judge to rule on whether a philosophical belief that sex is determined by biology is protected in law. “For people who don’t know: last December I tweeted my support for Maya Forstater, a tax specialist who’d lost her job for what were deemed ‘transphobic’ tweets. I write this without any desire to add to that toxicity,” she wrote. “This isn’t an easy piece to write, for reasons that will shortly become clear, but I know it’s time to explain myself on an issue surrounded by toxicity.