Katherine Schwarzenegger publicly supported her cousin Tatiana Schlossberg after the granddaughter of former President John F. Kennedy revealed her terminal cancer diagnosis. Schwarzenegger, 35, took to Instagram on Sunday, November 23, to share several screenshots of an essay Schlossberg, also 35, had penned for The New Yorker, which was published one day prior and detailed her battle with acute myeloid leukemia. "This is a profound piece written by my extraordinary cousin, Tatiana. It's been shared by many and should be read by all.