1. Originally Stan Lee called his new team The Merry Mutants, thankfully that was soon trimmed down to just The Mutants. Publisher Martin Goodman liked the new team concept but not the name, he didn't think readers would know what a 'mutant' was! So he strongly suggested to Lee that he change it, and The X-Men were born.2. Both Magneto and Professor X appeared in the first issue (published 1963). Stan Leeintended to reveal that the two were actually brothers. He just never got round to writing the story!3. Stan Lee later admitted that Yul Brynner was the inspiration behind Professor X's appearance.4. If you've followed the X-Men movies then you've likely seen a young Charles Xavier meeting and growing up with Mystique. In the comics it was a different character altogether. Juggernaut (Cain Marko) was his childhood companion, they were actually step-brothers and lived with together in the mansion house which would eventually become the location of the X-Men school. However unlike the friendship Xavier and Mystique were shown to share on screen, Charles and Cain did not get along.5. Charles Xavier's first student was 12 year old Jean Grey (who used the alias Marvel Girl). Next up was Scott Summers (Cyclops), who whilst honing his powers himself also assisted in tutoring Jean. Shortly after the pair were joined by Bobby Drake (Iceman), Warren Worthington III (Angel) and Henry McCoy (Beast). These five mutants made up the original X-Men line-up.6. Take a look at the first issue cover above and you'll see that The X-Men wore a lot of blue and yellow spandex - their first costumes. They've changed a lot over the years, but those original costumes finally appeared on the big screen in 2011's X-Men: First Class, however eleven years earlier the first X-Men movie paid tribute to the early outfits...7. In issue 3 it is suggested that Xavier has a crush on Jean Grey. It just happened in Xavier's mind, but was still quite risque considering the whole teacher/student scenario, and so was never mentioned in the original run again.8. The first new addition to join the X-Men was actually a non-mutant named Calvin Rankin (Mimic). He could copy the powers and abilities of any nearby Mutants thanks to an accident with powerful chemicals. He lost his powers quite quickly so only lasted a few issues.9. In 1966 Spider-Man was offered membership to the X-Men. He turned it down.10. In the comics Magneto is the father of three children - Lorna Dane (Polaris), Pietro Maximoff (Quicksilver) and Wanda Maximoff (Scarlet Witch). Those last two (the Maximoff twins) will be appearing in this years Avengers: Age Of Ultron movie, which is about the closest you're likely to get to an Avengers/X-Men movie crossover.11. In 1969, in a move to help increase the falling sales of The X-Men, the ranks were bolstered when Magneto's other daughter Polaris, and Cyclop's brother Havok joined the team.12. The most famous of The X-Men actually didn't join the team until 1975. Wolverine first appeared in a 1974 issue of The Incredible Hulk comic, the following year he was recruited by the X-Men for their Giant-Size X-Men issue 1 comic (above), and became a full time member from The X-Men #94.13. Wolverine came about when writer Len Wein was asked to create a superhero to help with Marvel's sales in the Canadian market. He decided to base his new creation on one of two common Canadian animals, either a wolverine or a badger. Thankfully, he went with the former.14. The X-Men hold the Guinness World Record for the best-selling comic book of all time. Issue 1 of the relaunched series (cover dated October 1991) was published with five different covers and sold over 8 million copies.15. Finally, in New X-Men #118 (cover dated November 2001) the word ‘sex’ was concealed throughout the comic at least 18 times, there is almost one appearance of the word on nearly every page. Eagle eyed readers might spot it in hair strands, bottles of whiskey, a hedge, a puddle, tree branches, protest signs and, thanks to some conveniently placed garden tools, on a lawn. The book’s artist, Ethan Van Sciver, said that he scattered the word throughout the book because Marvel was annoying him at the time and he thought it would be fun to inject a little mischief! Brilliant...