Gender refers to the socially constructed characteristics of women and men – such as the norms, roles and relationships that exist between them. Gender expectations vary between cultures and can change over time. It is also important to recognize identities that do not fit into the binary male or female sex categories. Gender norms, relations and roles also impact the health outcomes of people with transgender or intersex identities. http://www.who.int/mediacentre/factsheets/fs403/en/