I know that rape was widespread both among the allied forces and the Axis powers, but i haven't really been able to figure out in what way it has affected the war. Japan did state that comfort woman were used to prevent that japanese soldiers raped in occupied areas, which would make the population even more dissatisfied, though i have found no evidence that it actually helped in any way. Rape during the occupation of Germany, particularly by the red army is also a subject most people have knowledge about, yet i haven't seen a discussion about what effects it had on the general population.
So my questions are basically; why was rape such a common occurence? how did it affect the war, was it for example used as a psychological weapon? also what impact did it have on future generations?
EDIT: sexual slavery was the term i was looking for.
This is a massive subject and many books have been written. I only study the war in Europe, so I cannot comment much on the Pacific. For Europe, rape was a fundamental part of the war experience for many women. The rape of German women by Soviet prisoners is well known, but the use of rape and forced sexual slavery by the Nazis was equally common and debased.
[Dagmar Herzog's book Sex After Fascism] (http://press.princeton.edu/titles/7955.html) has an excellent opening chapter on sexuality under Nazism with a subfocus on sexuality in the camps.
Mary Lou Roberts's very recent work on rape by American GIs in France after the Normandy invasion also has chapters on the prostitution regime in France before the Nazi conquest and under Nazi control as well.
Finally, Norman Naimark's The Russians in Germany is a good place to start for that particular part of the equation.
As for your specific questions: Rape is common whenever there exists an extreme differential of power. Obviously, when an invading army is marching through your territory, such a differential exists. Other places where such a differential exists are also places where rape is common: prison, school, the home, etc.
Although I'm not familiar with it being used explicitly as a weapon in Europe, that does not mean that it did not have psychological effects, and it certainly did. The Roberts and Naimark books pay special attention to the effects of these traumas on the French and East German populations.