So much for zero population growth

The New York Times has a debate amongst a bunch of folks here about the issue of falling birth rates in developed countries:

A recent report from the Social Trends Institute points to falling fertility rates, not only in Japan and Western Europe, but also in China and the United States, and warns that "nations wishing to enjoy robust long-term economic growth and viable welfare states must maintain sustainable fertility rates of at least two children per woman". In the United States, the Pew Research Center recently said that the birth rate appears to be falling when the economy suffers. If a slow economy curbs the birth rate, and low birth rates hurt the economy, it sounds like a downward spiral.
As Japanese, European, Chinese, and American women have fewer children, is the global economy endangered? Or is that trend a healthy step toward balancing the population explosion in many developing nations?

Rico says he splutters when people talk about wanting to increase the birth rate; the planet does not need ten billion people...