Baby Mario is the infant version of Mario . He first appeared in Super Mario World 2 : Yoshi 's Island , released in 1995 for the Super Nintendo Entertainment System , and has appeared in several titles since . Little is known of Mario 's childhood , though the infant version of Mario , Baby Mario , first appeared in 1995 in Super Mario World 2 : Yoshi 's Island , and has often appeared in Nintendo sports games since that time .