repressed childhood memory

I was hanging out with Jenn and her boys a few nights ago when one of them asked me a question... I don't remember exactly what the question was, but it was one that had an obvious answer... not really a rhetorical question, but one more like this: "Eric, is the moon made of cheese?"
Now, that wasn't the question he asked, but it was something that he obviously knew the correct answer to... at that moment a distant, foggy memory came rushing to my brain... and I immediately began laughing.
When Andrea and I were kids and would ask ridiculous questions like this, my mom and dad would say: "what do you think?" and we'd answer the 'obvious' question correctly... at that point my mother and father both would reply: "very good retarded child."
The more I thought about this, the more I laughed... I couldn't believe my parents called us retarded, but I remember laughing about it back then too... but I don't know why I would have thought that to be funny back then as an impressionable, fragile young boy...
Upon further investigation, I asked my dad about this scarring detail in my life... he immediately began to laugh uncontrollably. He told me the 'very good retarded child' line was a punch-line to a joke that he and my mom heard around that time and then just always used it around Andrea and I to make us laugh...
Don't think that my parents would call their children retards... on second thought, that could explain so much...... (: