Key dates: Aug. 5, women's boxing makes its Olympic debut Venue: ExCel Exhibition Centre Big story: Although the fields are half as deep as in the men's competition -- 12 fighters versus 32 -- and although there are three weight classes versus 10 for the men, women's boxing will make its first appearance as a medal sport. Top U.S. prospects: Houston flyweight Marlen Esparza, lightweight Queen Underwood of Seattle and middleweight Claressa Shields of Flint, Mich., all have a good shot at making the podium (all above). Others to watch: Ireland's Katie Taylor, arguably the best women's amateur in the world, is a heavy favorite in the lightweight division (132 pounds). Flyweight Mary Kom, a mother of two from India, is a five-time world champion. Little-known fact: Women's boxing was on the schedule in St. Louis in 1904 as an exhibition event, but just six women -- in all sports -- are listed as having taken part in those Games.