Drawing on data collected from over 8,000 millennial women in Australia, this book proposes a new theory of women's sexual identity that accounts for various sociocultural, historical, and interactional factors that inform women's sexualities. The author provides a new model for understanding changes in sexual identity among women. Each new chapter focuses on a new aspect of their model: the contemporary context in which women are navigating sexual identities; sexual landscapes and the degree of heteronormativity that characterizes various sexual landscapes; experiences of sexual violence and their potential associations with the sexual trajectories of women; and the potential health and wellbeing implications of changes in sexual identity. Taken as a whole, this text challenges the essentialist framing of the "species" narrative in favor of a more nuanced and socially situated analysis of women's sexualities throughout the life course.This monograph will be of interest to scholars and students in sociology, gender and sexuality studies, and psychology.