In the original games, mew was the most sought after pokemon. In an attempt to control the world, the villains tried to clone Mew, and ended up getting a really evil and powerful thing called Mewtwo.
Yet another opportunity to impose a moral agenda upon the kids who become obsessed with this game - Do the creators of pokemon believe cloning is wrong? We know from countless science fiction tales that it is dangerous to play god. Maybe they want us to consider to what end science is used when intervening in nature.