Why do we have gender roles?Watch
Gender-roles are better titled: "Optimum gender behavior"
Think of it like evolution, but in terms of societies and cultures.. Many cultures and societies develop over many thousands of years. They compete for resources, go to war, try and survive natural disasters.. etc.
Of those many many cultures, the strongest ones are the ones that survive, go on to dominate the world, and have their practises spread or copied into other cultures who want to either copy their success or avoid annihilation.
So after thousands of years of societal development, at each stage we see, generally speaking, that the most succesful societies have the most succesful ways of organizing their people, that lead to the best societal effeciencies and productiveness. That includes how the two sexes/genders organize themselves.
But these aren't fixed, and they change, depending on the conditions of the time, enviromental/technological/educational etc.
So take 500 years ago:
Back then, the most optimal way to organise a society was to have most people farming/producing the food a society needed. That meant lots of rural families. For the rural family, what was the most optimal way of organizing? Most of the work was manual-labour in nature, and most of the jobs in and outside the farm were manual in nature, meaning that men are more efficient. At the same time with awful infant moratlity, to keep populations up, families needed many many children to hope a few survived. So you have work that by nature is physical (suited to men) and childbearing that would take 10 years and occupy a woman for large parts of her younger life (only able for women).. then you have the fact that without refridgeration or electrisity, maintaing a home was much more work, and you end up with the optimum arrangement of: Man works. Woman looks after kids/home, and works when possible as well.
But today, is that the most optimal way?
Now with technology, most jobs are not manual in nature.. so men are not always better at them.
Now with better medical care, women don't need to give birth 8 times to keep 2 alive, so they aren't busy for 10+ years being pregnant/looking after babies
Now we have efficient food-production which means the vast vast majority of the population don't need to be engaged in farming..
Now we have contriception and education which have changed the relationship of the sexes.
So now the most efficient way to organise a society, as seen by the richest and most succesful societies of today, isn't a woman at home and a man at work. It isn't strong men and mothers any more...
The problem is that society always lags behind technological/enviromental change. As a golden rule, societal norms always change slower than circumstances.. so what people who get annoyed about gender-norms are actually being annoyed at, is the delay. What they are seeing as the most optimum way for the genders to behave is X, but society is still telling us its Y, because society hasn't yet caught up with the recent progress/advancements.
They become feminists, because the societal function of feminism is to force society to keep up, and to bridge the gap between the old optimum arragenments and the new potential ones. They don't quite understand how their movement fits in historically, and it annoys me.. but that's the purpose they serve (when they are doing their jobs right), to force society to update itself to the newly possible most optimum arrangement.
Anyway, that's your short version of gender roles, how they develop and change.