The fact is, western military traditions it sexist for no good reason. Yes, the strongest woman will be weaker than the strongest man. Yes, it you take a sport like swordfighting, the best woman will be at the level of the 50th best man. But we're not talking about taking champions on a 1 on 1 duel here. We aren't even talking about fighting. What really matters in armies is endurance, and women are close enough to men on that that it shouldn't really matter.
And even if you want to think of war as a succession of duels, war have changed in the last century. Women are just better as shooting than men, especially when standing.