What's amazing to me is the number of Chinese families who "missed the memo". I know a lot of people born after the original policy who have one or more younger siblings. Also, penalties varied widely. I've met a few parents who said "It's ok, we'll just pay the fine." Don't forget that the the old policy had quite a few exceptions. Of those with families I've met, I don't think I know very many only children with no aunts or uncles.
As standards of living improve, average family sizes go down. Individual exceptions happen, but the averages hold up well around the world. If things continue on this path, world populations should peak somewhere in the 10-11 billion range, and then will start to slowly decline. Who knows, some countries may eventually put in a minimum 2 children per couple policy.