World of Origin's Age of Renewal
a) Sorcerers are practically nonexistent in this campaign setting. As they are defined in the Player’s Handbook they simply do not exist. The only “true sorcerers” are the dragons.
b) The various dragons, with the exception of the gem dragons who founded psionics, were the ones who discovered (some would argue invented!) arcane magic. This is why magic runs through their very veins, and why only they can truly spontaneously cast, control, and create it. This is also why almost all arcane spells were originally created by dragon, since they do not have the same difficulties learning spells and creating new ones as other races due (this means dragons/dragon sorcerers learn spells as it is described in the Sorcerer’s entry in the PHB).
c) The only race aside from dragons who can freely taking the sorcerer class as they desire are Half-Dragons. This applies to Half-Dragons of all types, except for Half-Gem Dragons.
However, Half-Dragons still face the same difficulties learning new spells as all other races, and must still use the required components to cast their spells.
d) The only other way for a creature to be eligible for the Sorcerer class is if it is directly descended from a non-gem dragon ancestor. This must be reflected by possessing at least four Dragon Heritage Feats (see the Draconomicon and Races of the Dragon).
However, these creatures still face the same difficulties learning new spells as all other races, and must still use the required components to cast their spells.