In my opinion, the short answer is yes, but it depends on the op-tempo, environment, and what's going on. Each person is different, male and female, of their physical and mental endurance abilities. Secondly, we don't fight wars like we used to. There is, however, still jobs in the military such as SOF communities and the infantry where physical fitness and mental endurance is needed.
Take for example a fully loaded Marine. I'll use myself. At 6 ft, and 195 lbs, plus another 60 lbs for gear, ammo, weapons, etc, you're looking at 255 lbs +/-. Should I get wounded and can't move, someone, or group of people are going to have to carry me, sometimes over a distance. It would suck more if there was no stretcher or vehicle near by. I've just created a liability b/c I'm wounded, but so are the others who are inept and can't carry me.
Another example that comes to mind is Infantry Officer's Course for the Marines. As a graduate of that school, it's no joke. The Marine Corps did a pilot program by admitting a few select females into that school, all supposedly volunteers and in good shape. They were expected to pass the same standards as their male counterparts. All didn't pass and/or dropped out. http://usnews.nbcnews.com/_news/2012...ry-course?lite
While those few females not passing may not mean anything (small sample size), and there could be in fact females that can pass, males have not passed that school either, and I've seen weak males Marines in my time in.
I'm neutral on the subject, and it's a different military these days. If males and females can pass the standard, great! If not, then perhaps they should look into another occupation.