Midget (3.5e Trait)
From D&D Wiki
You possess a rare gene which causes you to be much smaller than most members of your race.
Prerequisite: This trait is genetic; you are born with it. Therefore, it must be taken at 1st level.
Benefit: You gain all the benefits of being one size category smaller than what is normal for your race (better armor class, attack rolls, and Hide checks).
Drawback: You suffer all the drawbacks of being one size category smaller than what is normal for your race (worse bull rush, grapple, overrun, & trip checks, use smaller weapons, and lower lifting and carrying limits). Your movement speed is also reduced by 5 feet per round.
Special: Rules for different sizes can be found under Big and Little Creatures. Cannot have the Giantism Trait.
Roleplaying Ideas: You can pretty much play this one however you want. Your character might be sensitive about it, he might be proud of it, or he might be indifferent.