To add my thoughts to this, it's partly because a lot of girls just need to get over the fact that other people will watch them try something, and most likely fall a few times. Once that's done, there's a huge fear factor. A lot of times, it just takes a push, and many guys aren't willing to push a girl to try something for some reason. This may or may not be true about most girls, but a lot of times, I'll think too much about the negative things that could happen to me if I fell and whatnot. Maybe some girls just aren't motivated, or don't see it as being appealing or whatever, I don't really know.
Camps such as Progression are really cool because you're surrounded by girls, and while everybody is at different levels, there isn't that huge of a contrast between 'good and bad' skiing. Also, everybody is really supportive of each other, and sometimes you need somebody to cheer for you no matter how terrible you were.
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