For those who have played first Gen Pokémon R/G/B/Y or Third Gen Pokémon FR/LG, may remember this particular part of the game. On Cinnabar Island, you can find an enormous manor called "The Pokémon Mansion", and as we investigate it's depths, the player will start to notice some sort of odd books that actually are logs from an experiment.
In those, it is said that Mew was found in a southern area of America, and the researchers who did the discovery tried to replicate the DNA of Mew; that lead to make it's clone, the first human-created and mighty Pokémon Mewtwo, and maybe overrated.
In one of those entries, you can read a very particular date, February 6 to be precise, and it says that Mew gave birth... Well, thats odd, since we all pokémon players know that Legendaries can't breed, so... anyway, fuck logic it's Pokémon, for me is much better to call it a clone than Mew's son.
So you have it, today is Feb 6, so our very apreciated pokerfucking legendary Pokémon has to celebrate his birthday.
Yay! Happy birthday Mewty!