Now that I think about it, it is a valid question because Obi-Wans ghost told Luke that Yoda was the Jedi Master that "instructed" him. In Yoda's hovel when Luke first meets Yoda, Obi says to Yoda, "was I any different when you first taught me?" Maybe when Yoda was trying to put Dooku in his place before the fight, sort of like saying "I remember when I changed your diapers". Saying that doesn't mean that you were some bodies parents, it just means that you babysat the person possibly when you were a kid, or something. I mean we all know for a fact that Obi's Master was Qui-Gon, but he says that Yoda was his instructor, which from AOTC, Yoda teaches all younglings at some time.
Go big or go home.