It is simply no longer the case.
for me an equal relation ship means that each of our wishes, goals and needs are of equal importance. it can mean that both partners work and split housework equally, but it also can mean something different.
why is that better than everyone just realizing their own wishes and goals? because this way a space for cooperation is created because we'll both end up working on and supporting each others goals or wishes, and also each of us are able to notice if there is a conflict between each of our goals and wishes, and then we can work them out.
Some mothers have 5-15 kids!
Also that time has passed. All of Asia including south and south east are basically at replacement rate. Africa averages higher but not by a whole lot more and that number is dropping quickly.
There’s a reason women from wealthy families never work and dedicate all their time to raising kids.