Well, this has been a thread and a half.
There are few innate differences between male and female infants, and what there are are purely structural rather than cognitive. Infants are socialised from before birth, expectations are placed upon them at all levels of social control, from families, where this socialisation is often subtle and leads to the kinds of "gotchas" that we see a lot on here. Little things like "ooh, boys will make a gun out of anything" are simple cognitive bias at work, girls play with objects in the same ways as boys, but where a boy will have made a "gun" out of stick, a girl will have made something else out of it according to those observing the behaviour.
This continues at school, where "boys will be boys" and girls should be seen and not heard. And I know someone will come back at me with the weird trope of school being set up to what girls are "good at", sitting still and working quietly, but that makes no sense at all, because for years girls were not allowed to attend schools and school at the time consisted of boys sitting at long rows of desks, sitting still and working quietly, which begs the question; is it just because now boys are experiencing competition with girls that they're doing less well, and what can men do about that apart from grizzling about how education is oh, so feminised?
I could go on and on about how the different expectations and socialisation of the sexes from before birth are responsible for the differences seen in male and female adults, but I suspect it would get boring.
Just one last thing... women have always fought in wars, they just haven't been given a uniform and a weapon with which to do it. Rape as a weapon of war has been documented since the dawn of time and continues to this day, even in theatres of war where you wouldn't expect it and from armies you would expect to behave better.