A recently published fragment of the fourth-century speechwriter Hyperides contains a speech for the prosecution of Timandrus, accused of mistreating four orphans in his care. This article draws out from the fragment three important contributions to our understanding of Athenian conceptions of family relationships, particularly the relationships of marginalized groups: girls and enslaved people. First, the fragment constitutes a rare portrayal of a relationship between two sisters. Second, the fragment clearly articulates the idea that affective family relationships are not a biological inevitability but arise from socialization, a departure from other fourth-century thinking. Third, the speaker applies this statement to enslaved people, claiming that the separation of children from close family members is so cruel that even slave-traders avoid it in their sale of human beings. Though this claim seems to have been untrue except in a very limited sense, its place in the argumentation of the speech assumes broad recognition of the existence and value of family relationships between enslaved people, vivid evidence of the paradox that slave societies recognized the humanity of people they simultaneously insisted were subhuman.