The reason for the study was to find out why women were increasing their numbers in other sciences but not in computer studies. It turns out, it's the people they would have to hang out with.
This article in Science Daily puts it less starkly, saying it is because computers are so often found in unappealing locations and have unappealing geeky associations, but we know what that means.
They brought women into rooms that had either Star Trek posters, video game boxes, and Coke cans (stereotypical computer surroundings) or nature posters, a dictionary, and coffee cups (non-stereotypical). They told the women to ignore the surroundings, because the room was being shared with another class. Then they gave them a questionnaire about computer stuff. Women exposed to the geeky stuff had lower responses toward computers on the survey.
They did other, similar experiments, all showing more men like that kind of mini-macho geeky stuff than women. In other news, the sun will rise in the east today.