There's been so much politically correct drivel in this thread that I just have to state the obvious....Basic Biology. The male (of Homo Sapiens) is built for fighting, the female is not.
Females are much better at many things over their male counterparts but physical combat is NOT one of them. (And of course...in a planet of Billions of people, there will be exceptions....but they are far and few between...this isn't Tomb Raider or Resident Evil. There is an obvious reason that there is no such thing as a female Navy SEAL.
A man's bones are denser and usually larger, his skin is much thicker, more rugged, and more resilient to impacts (women have much more delicate skin...they bruise easily as their skin thickness and collagen content is much less). A man's eye's are recessed deeper in his skull to accommodate blows to the head without causing as much damage to the vision of the combatant. His skull is thicker, including a much more pronounced forehead, brow and jaw, also as a way to withstand violent confrontations with beast or man. A man has more speed, substantially more muscle mass and power...and a greater adrenaline rush in a fight or flight situation than a woman. Men have a greater ability to focus on one task, especially when in a life threatening situation and are less predisposed to "freeze" and panic. During the stress and turmoil of a life or death situation, gross motor skills take over both females and males, so any advantage females have in agility or fine motor skills (women often make the best sharpshooters and snipers) are completely eclipsed by raw survival instincts....here...only power, speed and resilience counts.
Our biology has built the males to protect and hunt.....and the females to nurture and socialize..thus females make much better communicators.
In a life and death situation, I can't imagine any female that I wouldn't be able to completely incapacitate with one blow....nor can I envision a women who is capable of landing the same on me, with equivalent power, momentum and speed.
Women serving in the military on the front lines where hand to hand combat is likely?...Probably not the best idea....taking political correctness to the point where her life and others around her hang in the balance.
Spare me the arguments that...."I don't have a problem as long as they can do the same job as anyone else"....The performance standards in Canadian and American military recruitment have been set to a level where MANY women can now successfully pass. Only the best women could have possibly passed recruitment standards before. This allows many men and women, the ability to serve in dangerous situations, where their bodies are not tough enough for the task.
Since women are much better multi-taskers then men...I would much rather see females commanding men..commanding vessels..and strategizing military manouvers....then implementing hand to hand.
There are no doubt some women that could kick the living crap out of me......but they are probably close to one out of 10,000. As for men....probably one out of 20.