I have parent categories and subcategories. Will it be harder for the subcategories to rank well because they have a parent category? The URL is longer, for one. I am just wondering if I should not have parent categories. I have one category page doing really well and I am trying to boost the others (most of which are subcategories) and this is a concern for me. Thanks!

Edit: I also have a category that has 2 parent categories. I want it automatically in those 2 categories and one of its own. By itself it is very important keyword. Is this ok or should I have it be a parent category?