My links are showing up twice in the sidebar

I have 2 categories of links. One is called ‘links’ the other is ‘blogs’. In my sidebar.php if i do wp_list_bookmarks(‘category_name=blogs’) the blogs category links will show up twice in the sidebar. If i put both wp_list_bookmarks(‘category_name=blogs’) and wp_list_bookmarks(‘category_name=links’) the two categories of links show up twice. If i just use the standard default wp_list_bookmarks() everything is fine (they show only once). But why are the links showing up twice when I add a parameter to it?