Stan Lee respondeu a essa pergunta em uma entrevista com Eric Spitznagel da Vanity Fair (março de 2011). Você pode ler a transcrição em ComicBookMovie.com .
VF: If it weren’t for the Comics Code, would the Hulk’s pants have ripped off like his shirt?
Stan Lee: I guess it probably would have. So occasionally the Code did some good things.
VF: Did you ever try to make sense of the Hulk’s magical purple pants? Why did they always conveniently remain intact while the rest of his clothes were ripped to shreds?
Stan Lee: I just figured that Bruce Banner had probably been a friend of Reed Richards [Mr. Fantastic from the Fantastic Four], and Reed had given him some elastic trousers. There’s an explanation for everything, but you may not be technically advanced enough to follow me on all of this.
Isso é conhecido na TV Tropes como Magic Pants .