Does finance play a part in the decision to have children or not?

This question was posed on an internet discussion board recently. One of the concerns people have when thinking about whether to have a child or not is whether they can afford to have children.

I've only had a few clients for whom this was the prime concern however ~ for most people there are other issues affecting the decision ~ and it is rarely purely a financial question. Yet it is a big factor - can I afford to have children now? Should I wait? How long to wait? How much money is enough money?