"Women aren't big and strong enough for combat." I'll buy this when someone explains why the Marine Corps will cheerfully accept a 4-foot-10 male recruit who weighs 96 pounds.
Sure, the Marines will make a man out of him, but even if they water the guy with Miracle-Gro, they won't be able to turn him into a 6-footer. The average man may be bigger and stronger than the average woman, but plenty of women are bigger and stronger than many men. Why discriminate based on gender when you could have straightforward, task-specific strength requirements?
In any case, in a war that mixes high-tech weaponry with low-tech hazards, being big and strong isn't all it's cracked up to be. You don't need to be big and strong to fly a modern combat jet, and size won't help when you're up against suicide bombers and improvised explosive devices. Why do we believe that bigger people make better soldiers? In Vietnam, an army of big, strong American men fought an army of small, slender Vietnamese men -- and lost.