Who's your daddy?

Today Joshua announced that he has a different father than Nathan. After reassuring him that they both had the same father, he then insisted no and that his father's name is Joshua. Added to that, apparently I'm not his mother either. His real mother is some woman named Elizabeth. When I asked him who I was then, he said that I was the babysitter. I then asked him when his real parents were going to come pick him up because the babysitter was done.