This chapter is based on ethnographic fieldwork in a neuroscience laboratory on whose research reports of the discovery of a monogamy gene were based. This chapter demonstrates how assumptions about human monogamy are naturalized and shape the notions of the normal (sexual/social/pair-bonded) and the abnormal (asexual/asocial/promiscuous) that are built into the modeling of gene-brain-behavior connections in contemporary neuroscience. It analyzes the laboratory’s publications and practices in order to hold the discursive production of difference and the material conditions of possibility for that production within the same frame. It examines slippages in terminology and choices about its deployment, models that code monogamy as a meaningful biological category, and experiments that measure it, in order to trace the material-discursive normalization of coupling, with all of its complex historical entanglements. The chapter’s analyses suggest that the naturalization of monogamy depends on the imposition of sexuality as an interpretive grid for bonding behavior.