Ah, story time, children...
A long time ago in a land far, far away (Fallujah, Iraq 2005) a supply convoy was hit by an IED on their way into our base. Word got to our company that there were several casualties including a few Marine women and that they needed more blood than we had on hand. We were an infantry company, so all males, and almost everyone immediately volunteered to give any amount of blood they needed in order to save a few females none of us have EVER MET. Now imagine training, living, and fighting with a female and having her get wounded in the field and imagine the effect it would have on the males. It would result in complete command breakdown, orders ignored, orders not given, more casualties and the unit becomes combat ineffective. Females also serve as a distraction even when they aren't in mortal peril. The powers that be like to keep us grunts in a constant state of aggravation, and part of that is putting as much distance between us and that which we desire (money, booze, violence, and sex)... its what makes us so ferocious in battle, we direct our pent up rage at something or someone we are legally sanctioned to shoot, destroy, blow up, or just beat into submission.
Another story, this time from Afghanistan in 2008. My good friend who had re-enlisted after I got out was there and witnessed history in the making. The Marines actually had a unit of all females to be sent on combat operations... Mission result: 60% pregnant within 2 months in-country.
I say let the females do combat operations, but not Infantry. Military life is a completely different world from civilian life, and Infantry life is a completely different world from the rest of the military. Please note that my views are from a Marine perspective, the only thing I know about how the Army runs things is that they fuck everything up. If that offends anybody with any association with the Army, let it be known that I've had to dodge incoming .50 caliber fire to walk from my bed to the porta-shitter thanks to some asshole being all he could be.
EDIT: I actually voted #2 before I decided to go on this rant, but I guess my view qualifies as "other".