This paper investigates the discourses in defense of morality that arose around the book Mademoiselle Cinema, of Benjamin Costallat, first released in 1923. The work was Brazil's biggest publishing success of the first decades of the twentieth century and came to be collected by the police in 1924, on charges of being offensive to moral and good customs. The reason for that was the behavior of its central character, far from that which was expected for the girls of her age. The seizure of the book has aroused intense debate on what should or should not be considered moral / immoral and even on gender roles in society. In this article we investigate the intersection between these lines, aiming to demonstrate the differences and the moral consensus that arose between them.