All societies are based on rules to protect pregnant women and young children. All else is surplusage, excrescence, adornment, luxury, or folly, which can and must be dumped in emergency to preserve this prime function. As racial survival is the only universal morality, no other basic is possible. Attempts to formulate a "perfect society" on any foundation other than "Women and children first!" is not only witless, it is automatically genocidal. Nevertheless, starry-eyed idealists (all of them male) have tried endlessly and no doubt will keep on trying. - Robert Heinlein
And if the women try to replace the men in their role, the men will let them, and just go off to amuse themselves.
Happens every time it's tried.