Sex used to rule. Now gender identity is on the throne. Sex survives as a cheap imitation of its former self: assigned at birth, on a spectrum, socially constructed, and definitely not binary. Apparently quite a few of us fall outside the categories male and female . But gender identity is said to be universal we all have one. Humanity used to be cleaved into two sexes, whereas now the crucial division depends on whether our gender identity aligns with our body. If it does, we are cisgender; if it does not, we are transgender. The dethroning of sex has meant the threat of execution for formerly noble words such as woman and man . In this provocative, bold, and humane book, the philosopher Alex Byrne pushes back against the new gender revolution. Drawing on evidence from biology, psychology, anthropology and sexology, Byrne exposes the flaws in the revolutionary manifesto. The book applies the tools of philosophy, accessibly and with flair, to gender, sex, transsexuality, patriarchy, our many identities, and our true or authentic selves. The topics of Trouble with Gender are relevant to us all. This is a book for anyone who has wondered Is sex binary? , Why are men and women different? , What is a woman? or, simply, Where can I go to know more about these controversies? Revolutions devour their own children, and the gender revolution is no exception. Trouble with Gender joins the forefront of the counter-revolution, restoring sex to its rightful place, at the centre of what it means to be human.