Its an innate, evolutionary trait of men that they are altruistic and willing to sacrifice themselves to be of service and protect others. Women on the hand are generally the beneficiaries of such a sacrifice and do not appear to be evolutionary inclined to do so themselves. But are there evolutionary reasons for women to sacrifice themselves for anyone at a given time? Perhaps their baby or children? And between what ages would they be willing to make such a sacrifice? Would a 17 year old mother sacrifice herself for her child, or from am evolutionary standpoint would it be better for the tribe if she stayed alive to reproduce again later or to protect her other kids (if she had any)? I could see post fertile women (approx 45+) should be willing to sacrifice themselves but then menopause kicks in and they are generally nastier and more selfish than before.