Sex is complex. Humans are simultaneously more similar in their sex development, and more diverse, than is commonly appreciated or understood. Females and males are not made of wildly different ingredients. The potential to have intersex variations-to be born with atypical sex characteristics-exists for all humans in the first few weeks of their prenatal development. 1.7% of people actually go on to be born intersex. However, most of us know little about intersex variations. This is only partly due to their occasional invisibility. Intersex people have historically faced deep social stigma-the assumption that they were simply bizarre aberrations from the human norm. Furthermore, intersex infants have been widely subjected to systematic institutional mistreatment, particularly within medical settings. Finally, some people with intersex variations have simply tried to integrate themselves unnoticed into the socially accepted categories of male and female. Drawing on stories and statistics from the first national study of intersex the book argues for a distinct 'Intersex Studies' framework to address intersex issues and identity-foregrounding people with intersex variations' own goals, perspectives and experiences. Collected in 2015 and arranged in thematic chapters, the data presented here on 272 individuals gives a penetrating account of historically and socially obscured experience. This book is an important and long-overdue contribution to our understanding of human sexuality and a must-read for people with intersex variations, health practitioners, psychologists, advocacy groups, students, and anybody interested in knowing more about our diverse human make-up.