Ceph, if you click the "clearance closet" link on the bottom of the intro page, you can see that some are men's specific and some are women's specific packs. The Jam is instock for both genders, but the pinnacle is only available for women. Personally, I think the differences between the two genders is fairly minimal. The womens' packs have a slightly more curved waistbelt (wider hips) but the padding is so minimal that you probably won't notice this (at least on the older models, without the wishbone hipbelt)
Also as a general rule, you can tell which pack is for which gender depending on the color scheme. Men's packs typically use contrasting colors (e.g. blue with gray, green with gray) while women's packs using complementing colors (e.g. blue with lighter blue, or green with lighter green)
If you really want to get a pinnacle, it might be worth it to try the women's version. But if you want a jam, you might as well get the gender appropriate version while you can. Also, the women's packs are usually smaller in volume for their respective size. You usually lose around 5 liters for the same size pack when going from male to female.