Here's another way...go to the profile of the ancestor with the surname you want. The surname will be filled in the last name search box already. Just click the search button. On the next page that comes up, among all the links at the top of the page is one which says "limit to Watchlist." Click that. The list which comes up is just the people on your Watchlist with that surname. It includes the females, too. There are a whole bunch of options down the right side of that page to change the way you want to view the list.