LONDON (Reuters) - The expulsion of an American judo player from the London 2012 Olympic Games on Monday after he tested positive for marijuana prompted scientists to question the sense behind the drug's inclusion on the World Anti Doping Agency's (WADA) banned list. Few experts think marijuana, or cannabis - whether it's eaten or smoked - can do much to enhance the kind of speed, strength, power or precision that Olympic athletes strive for. ... More...