Using cross-cultural comparative approaches among 249 cultures, this study explores the uniformity in human preference to concealing mating to others. The research questions guiding this study are: 1) Is the preference to conceal in legitimate mating a 'human universal'? and 2). What evolutionary pressures have originated this uniformity? The author proposes the ‘cooperation maintenance hypothesis’, which is built from three premises: sensory stimuli evoke sexual arousal in witnesses, humans are trying to exert control over their mating partner(s), and there is a need to foster within-group cooperation. This hypothesis suggests that concealing mating serves as a behavioral strategy to simultaneously retain control over mating partner(s) and foster cooperation with others. The author states that more analysis is needed to explain this behavior in other non-human species. The findings show support for the widespread pattern of concealment or attempts at concealment.