juryguy: I don't know.  As a child I always wanted a sibling. I never was and still am not a very sociable person. I'm kind of a loner.  I always thought that it was the result of me being an only child, but now that I have two sons myself, I don't know anymore. My first child is just like I was: he doesn't talk to other kids, he's kinda happy doing his own thing or maybe with one only selected friend. My second son is the opposite, always chatting to everybody. 
So, now I'm wondering, maybe I'm not like that because I was an only child but beause that is just the way I am, period. Seems that way because my own son is not an only child and seem to have inherited that personality trait. :/