In particular they mention a British study that just came out late last year, which you can read here. In terms of combat effectivness -- which one would think ought to be the only consideration -- the British identified 21 factors they thought could plausibly be said to contribute to combat effectiveness. Women studied had negative results in 11 of these 21 areas.
"In three of the 11 negative factors, mitigation would be a significant challenge," the report says. "These are survivability, morbidity and deployability, much of which are predicated by physiology."
Those are some pretty important areas. Will they survive in combat? Will they suffer injuries that will hamper their teams? Can they be deployed at all?
The problems turn out to be related. Women suffer combat stress injuries much quicker than men, which reduces their ability to maneuver -- and also makes them less dangerous to their enemies, not just less likely to survive.
These studies suggest that the relative strength of women, compared to men, when carrying the combat load are likely to result in the early onset of fatigue. This is likely to result in a distinct cohort with lower survivability in combat. Similar research points to a reduced lethality rate; in that combat marksmanship degrades as a result of fatigue when the combat load increases in proportion to body weight and strength. The risks regarding survivability are therefore relative; these are about biology rather than character.UPDATE: I think this concerns me for two basic reasons.
1. We're doing all these assessments on what amount to closed courses. The whole reason to establish a closed course is to limit the risks: you can drive at speeds that would be ridiculously unsafe in traffic, or practice combat-driving maneuvers in a relatively safe environment before you have to go out and do them for real. The problem is that the armed forces will have to go out and do this for real at some point. If we discover in a three-month survey on a closed course that we're encountering morbidity and survivability problems that also impact the ability to effectively kill the enemy, we need to understand that the effect of this on a unit deployed at war for a year or more is going to be magnified substantially. For want of a nail, the shoe... the horse... the troop... the regiment... the battle.. the war.
2. That Congress and the military are glad-handing their way through this suggests that we're not listening to negative findings if they conflict with the great goal of 'gender equality.' Will negative findings from the battlefield be enough to correct us here? Or will we refuse to see it even then? 'Their command should have trained them harder'; 'their leadership didn't provide adequate support'; 'the environment is toxic for women'; 'who dares question that she got pregnant at deployment time?'
The danger is accepting a permanently higher number of American dead and injured to further our chase for this will-o'-wisp.