comic book science tells us how the Hulk works, it doesn't tell us how his pants work.
I know that if I grew like the hulk did they would certainly rip around the waste.
At least the latest film addressed that he actually buys pants several sizes larger to accomodate for just that.
Oh for Jesus.
No, comics don't tell us how the Hulk works, and cannot, because gamma radiation does not function like that. Comic book science just says, "This crazy shit happened, because this ain't the real world, and shut the fuck up, Poindexter." Which is fine because it's suspension of disbelief, right? Now, the thing is, you're willing to suspend your disbelief to accept that gamma radiation can in fact turn a man into a powerhouse with poor impulse control, but his pants...well, fuck those pants because that shit doesn't make sense?
And in the film, he buys goddamn stretchy pants. He even says this.