Gender apartheid is a way of thinking or behaving where men and women are treated differently and not treated equally. This means that men and women do not have equal rights or opportunities. For example, in some countries, women are not allowed to have a job or to vote. It can also mean that men and women have different rules they must follow and different kinds of activities they can do. In extreme cases, women may be physically separated from men and not allowed to be in public places.