I kind of go thru the same thing. In third grade, I knew waaaaay too much about sex. There were weird things I knew about what others had no clue what I was talking about. Sensations I knew about that I shouldn't have... and I have no recollection of my 2nd grade year at all.

So.

I have come to the conclusion it's possible and deal with it that way. Personally, I don't want to know. I'd rather know it's possible and just deal with it "as if it did" and it's been a little better.