Something that we accept mutually - Gender discrimination

It's always been like this since the beginning of humanity, even before we learn to segregate between male and female.
In the bible, the Christian god created Eve as Adam's companion. In this companionship, they both play different roles to create a balance. Adam was responsible to put food on the table by hunting, planting, building; Eve was to mend the housework, prepare the food, bear children for Adam. There were no protest on gender inequality but a subtle impression of acceptance to the idea on the basic, perhaps original, role between a man and a women.
This idea was never challenged by any cultures and it was universally, perhaps mutually, accepted by all man and woman. The balance was a perfect and ideal goal for every man and woman to pursue. It was then to believe only by keeping that balance will man and woman find, perhaps create, their own happiness. Before we knew it, gender stereotype was born.