Taking the fascinating 'scientization of the social' in 'modernizing' Europe as its context, my dissertation examines the texts and activism of German-speaking and British feminists during the years 1890-1914 to investigate how hegemonic scientific theories of gender, sexuality, and the body informed feminist claims for civil rights, citizenship, and social transformation. Additionally, I explore the arguments of scientific experts themselves, which served as the bases of feminist engagement. In so doing, I address three central questions: In what ways did claims of science enable feminists to advance claims for civil rights and social transformation? How and why did this discourse become available to them? How were feminist deployments of science shaped by the discourses in circulation, the historically specific contexts of their deployment, women's social status and access to institutions of education and communication, and women's gendered and sexed subjectivity? Within this study, Germany will serve as the primary case, with Britain as a comparative case. Germany is a particularly apt case, given its historical interconnections between scientific conceptions of gender and sexuality, political contestation, and state planning. Britain, home of Darwin and Galton--the two most influential scientific thinkers of the period-provides a good comparative case as claims legitimated by 'science' here were tempered by the political and social embeddedness of liberalism, despite a similar turn to science. In undertaking this project, I hope to broaden existing suppositions regarding women's relationship to science beyond that of victim and opponent; to study of the ways in which scientific theories of gender and sexuality become politicized and popularized; and to construct an intellectual heritage for twenty-first century feminist scientific scholarship that biologically deconstructs the meanings of gender, sexuality, and the body.