It's a good question to ask. Most people don't really decide based on wisdom.
In the US today, 90% of all households - with children or not - will go bankrupt before the parents pass away. Retirement and the medical costs of old age are beyond our earning power. I think people planning to be parents should seriously consider economic and social realities. Are you ready to bring a child into the world and raise him or her to be a gift to our troubled planet?
See my hub Go Green in Time: Stop Global Warming and Climate Change for more on the world our children are coming in to. (It will be off idle by Sun 12/2.