Katherine Vandam "Kate" Bornstein (born March 15, 1948) is an American author, playwright, performance artist, and gender theorist. Having been assigned male at birth and then receiving sex reassignment surgery in 1986, Bornstein says, "I don't call myself a woman, and I know I'm not a man". Bornstein has also written about having anorexia, being a survivor of PTSD and being diagnosed with borderline personality disorder. Bornstein has chronic lymphocytic leukemia and in September 2012 was diagnosed with lung cancer.
Bornstein and partner Barbara Carrellas live in New York City with three cats, two dogs and a turtle.