That US Army study was Bull swear word, like most US army "research" such as on dragon scale, the XM8 etc, complete and utter crap from incompetent half wits. Take your info from the Marines, who actually value a soldier regardless of gender, women can ignore pain easier and have a higher tolerance for general combat fatigue.
That and most the women in the military have been fighting their entire life so the average Joe Shmoe that joins up has to work up for a few years just to get up to their level. Ex military here, a female soldier is just as good as a male soldier, and don't give me this "Women should be weaker" bull. Its complete crap, maybe city girls or glam girls sure, but these are soldiers trained to the SAME standards as their male counterparts.