Gender roles refer to social and behavioral norms that, within a specific culture, are widely considered to be socially appropriate for individuals of a specific sex. These often determine the traditional responsibilities and tasks assigned to men, women, boys and girls (see gender division of labor). Gender-specific roles are often conditioned by household structure, access to resources, specific impacts of the global economy, occurrence of conflict or disaster, and other locally relevant factors such as ecological conditions. Like gender itself, gender roles can evolve over time, in particular through the empowerment of women and transformation of masculinities.