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.
1. The anabolic testosterone is a key factor in muscle development and bone density. While there is enough variety that on both ends of the spectrum, there is some overlap between males and females, on average men have ten times as much testosterone as women. Women are weaker on average. This is why sports events seperate by gender.
2. The myth about a higher pain threshold of women is based on observations of women during childbirth. However, it's now well known that during this time their body pumps out different chemicals. This increases their pain threshold during this time. From an abstract, "There was a significant decline in pain threshold after labor as compared to pain threshold during labor [...] Pain intensity using the VRS score was higher during labor than before labor [...] We found a significant rise in pain threshold during labor in term pregnancies." In fact, with the exception of pregnancy, it is men who have a slightly higher pain threshold.