This chapter explores issues of sex, abortion, and prostitution in the lives of girls in Chicago during the Gilded Age. In the late nineteenth century, some Chicago girls aged between twelve and twenty acquired unusual freedom and took the opportunity to make their own sexual choices. Labeled “bad girls” in the press, they shared a new sexual ethic with some adults who placed sexual expression at the heart of life and accorded girls the same right as boys to sexual freedom. Whether they were rebelling against Victorian morality, contemplating what to do about an unplanned pregnancy, or engaging in prostitution, these bad girls made their own choices and asserted agency and independence in a modernizing city.