The answer is simple. No matter how mankind has sought to gender equality, there are two things that no one can change. Firstly, to have children can only women. Secondly, every man can theoretically at least daily to conceive children, a woman is much less productive.
Automatically turns out that the woman - being more valuable in terms of the survival of the species. Hence - the need to protect "the weaker sex", cherish every beautiful lady. Therefore, all the responsibilities associated with the risk to human life or significant physical activity (to hunt mammoth to go to war or to "warring" go down into the mine, and so on) have been, and will remain a matter of a male.
The guy more, man less - in terms of survival of the species is absolutely unimportant. If the ranks of men strongly poredeyut even one indefatigable macho will be able to raise the birth rate in a particular town. That is why, incidentally, to the male change society as a whole will always be treated more loyal than to women.
But she will always have a casting vote in all matters related to the birth of children (and will hold on to it right to the last - at least remember the uproar when trying to legally register the consent of the lawful wife of an abortion). To give birth or not to give birth and when to do it - it will be a woman, and only this. It may of course take into account the opinion of the husband, but it is not obliged to do so.
Exclusively women's right to give birth - the most powerful lever of influence on individual husband (or lover), and the state, which will try in every way to support "motherhood and childhood" (ie women and children). But this pregnancy and the need to "obihazhivat" baby makes a woman more vulnerable: the decree and post-natal leave automatically means a break from work (which is not very fond of employers) and generally binds a woman to the house. Who in this period should provide the mother with the baby protection and financial well-being? That's right, man. That is why the family where the woman pulls on a "financial cart", and a man earns "on pins" look askance: when a family heir automatically loses "breadwinner", and it is somehow wrong.
Therefore, equality in the family (and in society) may occur, perhaps, only if humanity suddenly embody fantastic idea about the conception of children "in vitro" and growing them in incubators, as well as polls artificial feeding. But, by the way, even in such a case, a woman will be in a privileged position: after all, the number of eggs that she will be able to "sacrifice" for the work of reproducing the human species, to put it mildly, much less than the number of sperm that are able to take away from a man.