In the science fiction novel Spares by Michal Martin Smith, we are introduced to a society of the future in which wealthy individuals can clone themselves in order to provide replacement parts for their diseased or damaged organs. Is this practice morally permissible? (Consider the case in which such cloned individuals are kept in a coma-like state for the duration of their lives, unlike the case in the novel, in which those individuals are conscious and held as something akin to slaves.)