Chauvinism/Sexism is the belief that one gender is superior to the other.
Explanation:
The idea that leads to the superiority of one gender over the other rises through the belief of chauvinism, or in other terms, sexism. When a group of a particular gender propounds that it has an edge of superiority over the group of other gender, it can be concluded that the group propounding so is a chauvinist group.