I prefer the fan theory that Mario is the bad guy. The princess actually loves Bowser, and she goes along with the kidnappings in order to be with him. In Super Mario Sunshine, when it is revealed that Peach is NOT Bowser Jr.'s mother, everyone, including Peach, is surprised. Why would Peach be surprised if she had not given birth to one (or all) of Bowser's previous children? Mario is the bad guy, as he continues to steal the princess from her true love.
Anyway, Happy Birthday, Mario!