Tumultuous nineteenth-century political debates, fears of violent revolutions, and the rise of women’s rights campaigns in Britain, the United States, and France provide a context for considering Darwin’s theory of sexual selection and its engagement with feminism. The Descent of Man, and Selection in Relation to Sex (1871) identified sexual differences, male–male combat, and female choice in courtship as key elements of animal copulation, while insisting that male choice controls human sexual relations, ideas that inspired radically different reactions from feminists, who objected to what they regarded as Darwin’s sexism, and fiction writers, who highlighted women characters resisting patriarchal expectations and making independent decisions. The long history and profound consequences of the concepts of sexual difference and sexual selection call for careful consideration of the intertwining of Darwin’s scientific theories about sexual difference and choice with divergent cultural formations, ranging from social Darwinism to feminist theory, and propose a more fluid understanding of sex and gender that supersedes the earlier two-sex model.