The growth of the use af contraceptive, of the number of women as head of families, and of their leveI of education, together with their impoverishment are combined to the poor estate in which the health in Brazil is. We noticed that, enlarging this picture, a quick advancing of HIV/AIDS epidemics among the feminine population, infected, mainly, by way of sexual transmission. Up to now, the inexistence of a method, determined by women, to prevent the sexual transmission of the virus make urgent the discussion of the inequal relations between the genders, that keep women in an inferior position in the social and individual levels, and interfere in the process of decision taking related to their health and physical integrity protection. With this article we intend to discuss the complexity of the relation between gender and power that permeates the sexual encounters between men and women, delimitating and shaping, among other things, the possibilities of safer sexual practices negotiation.