Warren Beatty and Annette Bening's eldest daughter, Kathlyn (pictured top left in 2007), is living as a man and plans to have a sex change operation, according to the National Enquirer.
The 18-year-old reportedly has changed her name to Stephen Ira and has been attending university dressed in men's clothing.
Warren is said to be "devastated" by his daughter's decision, but he and Annette are trying to support her the best they can.
The couple are also parents to 16-year-old Benjamin, 13-year-old Isabel and Ella, 10.
Photo: ę Getty