French-born American artist Louise Bourgeois will be 96 this Christmas. Still producing cutting edge art, memories of a disturbed childhood have produced disturbing sculptures. Some of her giant spiders and plastic body parts are now part of a major retrospective at the Tate Modern. Alan Yentob goes to her New York home where young artists queue up to get her reactions to their work. He talks with Tracey Emin, Antony Gormley and others who have been inspired by this mischievous artist.