Kinship is disputed territory, investigated by anthropology, cultural studies, evolutionary biology, family studies, genetics, law, medicine, psychology, sociology, and women’s and gender studies. Kinship classifications change across cultures and over time. As measures of legitimacy and arbiters of social standing, such categories have significant consequences. In the contemporary world, kinship is in flux as a result of such developments as reproductive technologies, blended families, same-sex marriage rights, and shifting gender roles. Our kin is not limited to humans, however. We belong to a vast evolutionary family tree, the history of which may influence the ways we interact with kin and organize kinship itself. The 2013 MU Life Sciences & Society Symposium, Claiming Kin, will explore the evolution of kin groups and evolving notions of kinship.