This text explores encounters between hermaphrodites - people born with "ambigious" sexual anatomy - and the medical and scientific professionals who grappled with them. Alice Dreger focuses on events in France and Britain in the late 19th century, a moment of great tension for question of sex roles. While the feminists, homosexuals, and anthropological explorers openly questioned the natures and purposes of the two sexes, anatomical hermaphrodites suggested a deeper question: just how many human sexes are there? Ultimately hermaphrodites led doctors and scientists to another surprisingly difficult question: what is sex, really? The book takes the reader inside the doctor's chamber to see how and why medical and scientific men constructed sex, gender, and sexuality as they did, and especially how the material conformation of hermaphroditic bodies - when combined with social exigencies - forced peculiar constructions. Throughout the book Dreger indicates how this history can help us to understand present-day conceptualizations of sex, gender, and sexuality.