Fun fact, I once had an argument with some classmates that Spider Man and The Hulk should be invited into the X-Men, since Peter Parker got his powers from that genetically-modified spider venom screwing with his DNA, and The Hulk got his powers through radiation.
From a scientific standpoint, they're both mutants. My classmates responded that in order to be an X-man, a mutant requires some kind of "X-gene," which makes no sense given that the mutant powers of most X-men are unique.
Stuff like this is why I like Webcomics. That way, if you come across something as bad as All-Star Batman and Robin, at least you didn't pay the entry fee.