We might ban buying or selling horse meat in the US not for the protection of horses, but because we find it morally repugnant. Yet this moral repugnance is clearly not universal, and on some level may even be arbitrary, given France's attitude towad horse meat. What role, if any, should moral repugnance play in determining the rules of our marketplaces? Even if we want to eliminate the influence of moral repugnance, can we? Debra and Ken hold their noses with Al Roth from Stanford University, author of Who Gets What ― and Why: The New Economics of Matchmaking and Market Design.