Red, Blue, Pearl, Diamond - Who the heck knows.
Platina and Sapphire - Most likely from their fathers.
Gold - He lived in a Pokemon House, sooo
Green - Most likely from Prof. Oak.
Yellow - Pft, we all know this one~
Ruby - His Dad, as he taught Nana Take Down and Coco Iron Tail before hand.
Crystal - From her mom?
Yeah. xD