Prior to about the 1880s every country in the world ALWAYS had women in their military. These were the "Washer Women" who are reported from the time of Crusades (c1000 AD) till the 1880s. As to the Crusades, washer women were an old institution within BOTH Christian and Moslem armies (And existed in Byzantine Armies that operated at that time period). Arabs Armies tend to copy Byzantine Army formations Through Arabs units tended to be lighter armed and more horse and Camels). Byzantine Armies had been reformed just before the Arab Conquest from the remains of the last of the Roman Legions. Thus when these washer women first appeared in Armies is unknown, they may have existed in the days of the Roman legions but unreported. Washer Women being unreported seems to be typical, in the Militia Act of 1794, the Militia of the US was given a set formation, including how many men to a Company, but how many Platoon to a Company is silent and the fact that Traditional Platoons of the 1700s were made up of 20 men under a Sargent and those 20 men were assigned a Washer Women (The washer Woman tended to be the Wife of the Sergeant, but this was NOT required). Notice these women were NOT mentioned in the 1794 Militia Act, the various acts setting up how the US Army was to be formed. Washer Women were NOT even mentioned in the Civil War (Through if wounded, what they received as compensation was set by the same statute that set the compensation for the men). The reason washer Women were NOT mentioned was everyone knew they existed and by tradition every 20 men had to have one.
The tradition of Washer Women was so strong that Congress had to pass a Statute in the 1880s outlawing Washer Women when it was decided that the jobs such washer women were doing (Other then washing clothes which had been just one of they many duties) had to be done by people who had gone to school for such duties, and congress did NOT want to pay women to go to schools.
One of my favorite facts about the Crusades was after a battle there was always talk about exchanging prisoners. The first prisoners to be exchanged were always the Washer Women, no matter which side had "won". So you how DEEP washer women were in both armies by that time, and the tradition INCREASED as time went on.
Another story of the Washer Women was the shipment of an British Regiment to India in the 1850s. The ship the Regiment as on started to sink. It was discovered that all by a handful of the life boats were unsafe (i.e. only a handful of boats could take ANY of the members of the Regiment). The Crew of the Ship followed the tradition of the Sea of that time, claimed the boats for themselves and any other passengers who could fit on (The Crew First Rule). IT was the Lt-Colonel of the Regiment that told his men to stand fast and permit the women and children on the boats first (This is the first time "Women and Children" is heard on any sinking ship). The Officers and Men held their ranks tell the the Women and Children (Mostly the Washer Women and their Children plus some officers wives and children) were loaded on the life rafts that were usable. The Officers and Men of the Ship went down with the Ship, and the "tradition" of "Women and Children" First was started.
For more details read about the 1852 Sinking:
http://en.wikipedia.org/wiki/HMS_Birkenhead_(1845)
Anyway, after the 1880s, the Sergeants wives still were on the base and did most of what the Washer women had done previously. The only change was they no longer went to war with the men of their Platoon. This official period of no women in the Army lasted till WWII when the "Women Army Auxiliary" (WAC)s ere formed. The WACS (and the female pilots who flew planes, mostly from the US to either Britain of the Far East) were suppose to NOT carry weapon (But many were in France in 1944 and given the possibility of German counter attacks many were given weapon training in 1944 and 1945). Women have been in the US Army ever since. The number of Women in Army actually Jumped in the 1970s where do to the ending of the Draft the Army had a problem getting recruits (Do to the fear of integration, when Congress reformed the US Military in 1948, restrictions as to women and other minutes i.e. blacks etc) as to combat roles were listed for the US Navy (Including the Marines) and the then new US Air Force, but no restrictions were put women and Combat Roles in the US Army. Prior to the 1970s the Army restricted women out of Combat Roles by Regulation, but jumped at the lack of legal constraints in the 1970s.
The lack of legal Constricts as to women for the Army, while the Navy and Air Force had clear restrictions was do to the fact that same act not only formed the US Air Force but also better integrated the National Guard in with the Army. It was clear that Congress could pass clear restrictions as to the Navy and Air Force (And even the Regular Army) but when it came to the National Guard, the States had rights, including the right to select the officers. Technically National Guard Officers received two commission one from their state the other from Congress. Generally there is no problem with this dual appointment system, but Congress was worried that a State may appoint a black to head an all-white unit and if Congress refused to accept that commission, that would lead to a Court Case where the Supreme Court may find the Dual commissioning system violates the US Constitution (Which reserves the right to appoint officers of the Militia to the States NOT congress). Thus Congress decided the best way to avoid this issue is to leave it up to the Army itself to use its regulatory powers to prevent this from happening. By the 1970s no one was worried about a black being appointed an officers of an all -white unit any more, but the lack of statutory restriction was jumped at by the Army. This was the law from 1948 till the early 1990s when Congress decided to open up the Air Force and Navy to the same lack of statutory restriction as the Army has had since 1948.
My point is that women have served in the US Army since the founding of this country in 1607 till the 1880s, and again from WWII till present (Thus women were NOT in the Army for only a roughly 60 years period out of the last 400 years of the existence of the Army in this country, i.e. since the settlement of Jamestown). Thus your comment as to women bring in the military a "Recent Phenomenon" is just plain wrong, and the military did address this for centuries, basically by making rape a capital offense AND making the men of the unit the women belong to, responsible for her protection, as they are responsible for the protection of each other.
As to such rapes, I paraphrase Patton from WWII, he made a comment about rape by US Soldiers and expected such rapes to occur AND WANTED THEM REPORTED TO HIM SO HE COULD HANG THE RAPISTS. He knew, as most people know, it is the "freedom" to do want you want to that lead to the Rape. Rape does NOT occur because men need and want sex, rape occurs when a man, who wants to attack a woman, can do so. In Iraq I notice almost no cases of Rape of Civilians are being reported (They was one bad case where a soldier and his buddies raped a teen age Iraqi, but again it was more to show her "We can rape her" then any desire for Sex). The rape cases involve women in the Green Zone and other "safe" areas who are working with men in non-combat roles.
Even today, Women can NOT serve in the any Combat unit i.e. the Infantry, Artillery or Tank Units. Women can serve in Combat Support units like Combat Engineer, Military Police and other Maintenance units. Most women serve in other support units where the men who commit the rapes against them are also NOT going into combat. Many of the raped women are in medical units and being raped by fellow medical personnel. Both see the results of Combat, but no where near the level of Combat of the Combat units. This may be the results that the Combat units have no women to rape, but the more logically explanation is that the rapists in the non-combat units see Iraq as an opportunity.
No, the fact these rapes are occurring when women are NOT allowed in Combat units implies it is NOT Combat that is causing the Rapes, but that being in Iraq the Rapists believe they can get away with it.