The real issue with "women in the military" is alleged to be their male comrades.
We need independent high quality research, but it would not shock me if the data showed that military women in combat settings are exposed to an intolerably high risk of sexual assault from their male peers and superiors. The next question is then -- can this be changed? I would also not be surprised if we were to discover that this male behavior is extremely difficult to change, particularly when, as in Iraq, things are going badly.
Assuming research showed the risk was high, and that the probability of changing male behavior was low, then there are only two options -- strict segregation of combat forces by gender or removal of one gender from combat settings.