I'm looking at writing up a Mutant origin, for PCs who want to play a mutant. (I know there will be a hive mutant origin in Radical's Handbook but I'm impatient) For simplicity I'm planning on following the example for the unique background from IHB, taking an existing origin and modifying.
Right now I'm looking starting with the Feral Worlder as a base because it has the Characteristics I want (high S and T, low WP and Fel) and I think the Primitive trait is appropriate for mutants as social outcasts.
I'm looking at having Mutation as a trait replace one (or more) of the other Feral Worlder traits. The Mutation trait would allow a roll on the Lesser Mutation chart (table 12-3 on page 334). Being a nice GM, I would probably allow a player to either reroll or roll again if they get a purely negative results (like misshapen or malformed hands) but I don't feel a need to write that into the rules.
One thing I'm not sure of is which Feral Worlder trait to remove in favor of Mutation. Iron Stomach seems really appropriate for a mutant, so I don't really want to drop it, but Rite of Passage or Wilderness Savvy don't seem to be "enough" to trade of a mutation. I'm considering trading them both for Mutation... so a mutant would get the traits: Iron Stomach, Primitive and Mutation.
Thoughts?