Mega 2, nope, I am going to disagree. If Mario and Peach hooked up, wouldn't they be living in Peach's Castle? Besides, the game refers to the couple as "Mario's Parents". This is a small dinky-looking house in the middle of nowhere... Besides, during the YI intro, Kamek tells the Toadies that they must find Baby Mario (not "Mario Jr.") because he will one day cause many problems for the Koopas. Plus, Baby Mario is reunited in the end with Baby Luigi (not "Luigi Jr.") In any case, the only information we have to say that Mario and Luigi did NOT come from the Mushroom Kingdom to begin with is in the Super Mario Bros. instruction manuel. I'm inclined to believe YI because the SMB instruction manuel was made before Nintendo of America realized who big the brothers would become. They screwed a lot of other things up to make the game more suitable to Americans, like changing Peach's name.