Jazz, I hope you are right about the population leveling off. We need to be kinder to our planet.

You commented that "The average number of children per family in the US now is 2.2. I assume this is dropping some. Two children per 2 parents would seem to be the leveling off point, but we also need to factor in single people who aren't having children at all."

I believe that single people are already included in that calculation of 2.2, whether childless or not. Regardless, 2.2 is already about the replacement rate, since not all children born survive to adulthood. Perhaps you can expand on your info?