This article is from the X-Men Comic Books FAQ, by Kate the Short (email@example.com) with numerous contributions by others.
You're absolutely correct. The Doom Patrol came out in 1963 (the same
year as the X-Men), and featured Robotman, Negative Man, and Elasti-Girl
under the cryptic leadership of the Chief. Yes, the heroes were crippled
or maladjusted by the nature of them being heroes--Robotman was an
"omniplegic," Negative Man was wrapped in protective bandages, and so
on. The Chief did rule from his wheelchair, and their whole point was to
prove that even misfits and freaks could be a productive part of
society, despite prejudice.
The interesting thing is that so far as anyone can tell this was another
example in history of pure coincidence. The Marvel and DC creative teams
apparently came up with the ideas completely on their own.
It's really not surprising when you think about when this was going on.
Marvel had revolutionarized the comic book industry with the "Marvel"
style of superhero, who had the complications of dealing with real life.
Never ones to miss on the sales comparisons, DC began copying the Marvel
style. Pretty soon we had families of superheroes with troubles,
teenaged superheroes with troubles, clubs of superheroes with
troubles... it didn't take much imagination to go to the next
progression of "modern" superheroes, superheroes with physical troubles
based on their physique, or prejudice.
A man in a wheelchair would be the natural authority figure to lead this
team, since he'd be an iconic reminder that people with disabilities can
still be functioning people, while still not suffering from such a major
disfigurement that the Comics Code of the time wouldn't accept him as an
ongoing character. The wheelchair figure couldn't be one of the active,
crime-fighting heroes, because giving him the power to leave his chair
to fight crime would invalidate the whole reason to put him in a
wheelchair in the first place. Finally, the wheelchair figure had to be
a man, since this was still the 1960s.
After the leader is set, you fill your team to taste with your choice of
heroes suffering unwarranted prejudice. And after cancelling the book in
the late 60s, bring it back later to large acclaim: as one final bit of
trivia to further prove the existence of the Illuminati, both the X-Men
and Doom Patrol came back in their first "new" forms in issues numbered
94--UXM #94 and Showcase #94, although Doom Patrol had to get cancelled
one more time before they became highly acclaimed. Technically, the
"new" X-Men debuted in Giant-Size X-Men #1, but since we're allowing the
Doom Patrol to slide on a technicality, we'll do the same for the X-Men.