Are athletes who are born male but identify as female cheating girls? Tennis legend Martina Navratilova says they are.

“To put the argument at its most basic,” she wrote this weekend in an op-ed for the Sunday Times of London, “a man can decide to be female, take hormones if required by whatever sporting organisation is concerned, win everything in sight and perhaps earn a small fortune, and then reverse his decision and go back to making babies if he so desires.”