Focusing on the late eighteenth and early nineteenth centuries, this volume highlights the scientific and philosophical inquiry into heredity and reproduction and the consequences of these developing ideas on understandings of race and gender. Neither the life sciences nor philosophy had fixed disciplinary boundaries at this point in history. Kant, Hegel, and Schelling weighed in on these questions alongside scientists such as Caspar Friedrich Wolff, Johann Friedrich Blumenbach, and Karl Ernst von Baer. The essays in this volume chart the development of modern gender polarizations and a naturalized, scientific understanding of gender and race that absorbed and legitimized cultural assumptions about difference and hierarchy.