Butler examines gender, sex, psychoanalysis and the medical treatment of intersex people. Focusing on the case of David Reimer who was medically reassigned from male to female after a botched circumcision, Butler reexamines the theory of performativity that she originally explored in Gender Trouble (1990). David then renamed as a girl- Brenda, rediscovers her masculinity and goes on to live his life as a male again. While many of Butler's books are intended for a highly academic audience, Undoing Gender reaches out to a much broader readership.
Butler discusses how gender is performed without one being conscious of it, but says that it does not mean this performativity is "automatic or mechanical". She argues that we have desires that do not originate from our personhood, but rather, from social norms. The writer also debates our notions of "human" and "less-than-human" and how these culturally imposed ideas can keep one from having a "viable life" as the biggest concerns are usually about whether a person will be accepted if his or her desires differ from normality. She states that one may feel the need of being recognized in order to live, but that at the same time, the conditions to be recognized make life "unlivable". The writer proposes an interrogation of such conditions so that people who resist them may have more possibilities of living.