As a rule of thumb, a higher percentage of men are going to have the mentality necessary to be in combat and the military. Men are less emotional than women. Welcome to the world of the living. Is this always true, no? But fewer men will have the emotional issues women will if they are in the military. This is just genetics and the way humans are wired.

Lets not forget, in a time of war, it is life or death. Not only that, if someone freezes under the stress of the situation, it might also mean the lives of those around them. If I was on the battlefield, I want to know that the person next to me is going to do their job and do their best to protect me. If I have to watch them (because they are scared or can't handle it), I don't want them there. 

If a woman wants children, don't join the military. It is simple. I don't like water, so I didn't join the Navy. Why can't people understand life is about choices. Want the military, no kids. Stop making everyone bend to your choices.