
Basically, the game uses a "bravery" stat to determine which clothing characters can wear. Bravery can be raised over time, to the point where Neku can wear clothing that isn't necessarily designed for him -- like girls' dresses. This is brilliant because not only does it keep Neku from equipment that would give him another character's abilities and thus overpower him, the stat cleverly mirrors the real world -- as in, only exceptional bravery would allow a teenage boy to slip on a dress for its combat effectiveness.