An eye-opening account on what we get wrong about sex and gender and a “formidable challenge to our politics, on both the right and the left…informed by science, law, and personal experience” (Guy-Uriel Charles, Harvard Law School professor)—and how we can be a thoughtful, sex-smart society.

On Sex and Gender focuses on three sequential and consequential questions: What is sex as opposed to gender? How does sex matter in our everyday lives? And how should it be reflected in law and policy? All three have been front-and-center in American life and politics since the rise of the trans right movement: They are included in both major parties’ political platforms. They are the subject of ongoing litigation in the federal courts and of highly contentious legislation on Capitol Hill. And they are a pivotal issue in the culture wars between left and right playing out around the dinner tables, on campuses and school boards, on op-ed pages, and in corporate handbooks.

Doriane Coleman challenges both sides to chart a better way. In a book that is equal parts scientific explanation, historical examination, and personal reflection, she argues that denying biological sex and focusing only on gender would have detrimental effects on women’s equal opportunity, on men’s future prospects, and on the health and welfare of society. Structural sexism needed to be dismantled—a true achievement of feminism and an ongoing fight—but going forward we should be sex smart, not sex blind.

This “seminal book—the science, the law, the politics all explained so clearly” (Edwin Moses, two-time Olympic gold medalist) is a clear guide for reasonable Americans on sex and gender—something everyone wants to understand but is terrified to discuss. Coleman shows that the science is settled, but equally there is a middle ground where common sense reigns and we can support transgender people without denying the facts of human biology. She livens her narrative with a sequence of portraits of exceptional human beings from legal pioneers like Myra Bradwell and Ketanji Brown Jackson to champion athletes like Caster Semenya and Cate Campbell to civil rights giants like Ruth Bader Ginsburg and Pauli Murray. Above all, Coleman reminds us that sex not only exists, but is also good—and she shows how we can get both sex and gender right for society.