Rape perpetrated by American soldiers during WWII?

As the previous answers document, rape was common among American soldiers. Negro soldiers were disproportionately punished, however, this was partially a side effect of their role in the war since they were service troops in the back lines they had a much greater opportunity to commit rape than men who were fighting in forward areas from which civilians had fled.

Its important to realize that the vast majority of sex was "consensual", if you consider a woman prostituting herself for food consensual. Virtually everyone in France, Italy, Austria and Germany was starving by the time the Americans arrived so a woman could be bought with half a tin of food or any kind of currency (cigarette/chocolate) which the woman could convert to food later.

To give you a sense of what it was like, if you were an army soldier on a public road, young boys would run up to you constantly and offer their sister for some pittance amount of money. If you accepted, you would be led to a house or shack nearby where she would be waiting, often a very young girl. The money you paid would be used to feed the whole family, but when you came you would only see the young boy and the girl.

Americans also had a penchant for setting up large "warehouse" style brothels that Italians and French found extremely offensive, although the Germans and Japanese were ok with them. One of the reasons we have relatively poor relations with France and Italy, even today, 70 years later, was the way we treated them during the war.

After the liberation of Normandy, US soldiers felt like it was time for a 'reward' and French women soon started complaining about the behavior of the US soldiers in Normandy. Fear spread among the people in France and that fear is best explained in this joke:

"Our men had to disguise themselves under the Germans. But when the Americans came, we had to hide the women."

Mary Louise Roberts, a history professor at the University of Wisconsin, in her book "What Soldiers Do: Sex and the American GI in World War II France." stated that American propaganda didn't sell the war as desire and fight for freedom but as 'sexual adventure for soldiers'.

Life magazine, one of the prominent publications of the day, stated:

"France was a tremendous brothel inhabited by 40,000,000 hedonists who spent all their time eating, drinking and making love."

According to Wikipedia, U.S. troops committed 208 rapes and about 30 murders in the department of Manche.

In the book Taken by force, J. Robert Lilly estimates that there were around 3,500 rapes in the France committed by US soldiers from June 1944 till the end of the war.

So yes, there were "massive" rapes committed by US soldiers, and they were committed in France after the liberation of Normandy.

Semaphore's answer is excellent, as usual. Let me add just an anecdotal perspective.

Is their any evidence that rape was perpetrated by American soldiers during WWII?

My grand-mother, a teenager at the time, was part of a fairly active resistance network interacting with the British military. On the wake of the liberation of her area of France, her contact officer was dropped one last time behind enemy lines for no other reason than to warn them that their area would be liberated the following day and that an American unit was in charge. He advised for everyone, but especially young women, to stay home for a couple of days if they could. As far as she knows, no sexual violence was reported in her area in the ensuing days (all jewelries were robbed the very night of the liberation however).

This story suggests that sexual violences were common enough to be considered a real and well-known threat but it is incompatible with the claim that it was systematic.

Among the allies, have other armies been involved?

In French historiography, it is well-known that one of the first French large military victory against the Germans, the battle of Monte-Cassino, was accompanied by massive rapes of the local population. See here for instance but, if you read French, compare with here which is much better documented and casts severe doubts on some of the most horrendous stories. Similar stories are reported in the aftermath of the battle of Freudenstadt. Though an exact or even approximate number will never be known, an interpolation based on reported cases yields a plausible number of 5 to 15 thousands sexual aggressions committed by the French military. Using a similar methodology, J.Robert Lilly apparently estimated the number of sexual aggressions committed by the American military to be between 10,000 and 20,000 (but I don't know how accurate is his work).

Interestingly, I have never read allegations of sexual violence on the part of British soldiers.

I just watched a report on TV in Germany about a book recently published Als die Soldaten kamen (When the soldiers came). The author researched the subject and interviewed numerous survivors all around Germany. She conservatively estimates some 860.000 women and children were being raped by the allies, the dark figure perhaps twice to three times as much so she says. According to her, 190.000 were raped by the GIs alone.

My family from my fathers side were ethnic Germans living in Bohemia for centuries before the war. They were expelled by the Czechs and taken to a concetration camp. My father was around 7 years old by then and told my he had seen how Germans were killed on the streets by their Czech neighbours. All her life long my grandmother talked about the camp and I remember her in her last days before she died at 96, she was heavily halluzinating and thought she was being deported again.