Sexism
Sexism is discrimination against people according to their sex, based on the belief that one sex is superior. It is most commonly used to refer to discrimination against women, but has increasingly come to mean discrimination against either gender. For example people may hold sexist beliefs that one gender is less capable of doing a particular task e.g. women are no good at manual work, men are no good at housework. Sexism becomes more damaging when it begins to threaten a person's potential by preventing them from doing something. For example a woman may not be allowed to apply for a particular job, because it is considered that she would not be capable of performing it as well as a man.
During World War Two in the UK men were away fighting, so women had to take on many of the roles that were previously thought only suitable for men e.g. driving buses. This had an impact on changing attitudes, because people (both women and men) came to realise that women were just as capable at doing these jobs.
In some societies there is a strict division of labour between men and women. This may be a result of cultural traditions, or may have been worked out to be the most efficient way of getting things done. For example women may do the majority of the childcare, because they are breastfeeding new babies. Men may perform more of the manual tasks because they are stronger and able to carry more. This is not necessarily sexist discrimination, but it can lead to stereotypes about the tasks men and women are capable of doing.