Gender Vs Sex
Sex is the biological differences between women and men. That is say the only differentiation of women and men is the sexual reproductive organs which cannot be changed. In simple terms it being either female or male where as gender is the social relations and differences that differ from society to society, culture to culture or country to country that are learned or acquire by being in a particular set up. These are not static but can be changed.
Gender roles are those roles work that are carried out by a certain grouping for example cleaning the house, caring for children, being an accounts or being an electrician. These roles can be carried out by either males or females.