Well said, but I think it also depends on who's working and what jobs they're doing.  One couple I know got married in their 20s, and they both have jobs earning over $100k/year.  They could easily afford to have more than one kid if they chose to (which they might have; I lost touch with them a few years ago).  On the other hand, some husbands are old-school and want their wives to stay at home and not work.  In situations like that, I can see how a person could go poor pretty quickly. 

I'm of the opinion that people should build a career before settling in to the family life and that most people should wait a while before getting married--never mind having children.  For one thing, a lot of marriages fail.  I have a feeling that has a lot to do with people being in love and being impulsive and making the decision to get married before they're ready to.  If you find your career path first, I think you're much more likely to be able to support a family and not go broke trying to do so.

It drives me nuts when I see videos on youtube or TV or wherever, and there are children who look like they're starving to death.  It's irresponsible to bring kids into what's surely going to be a world of poverty for them.  If a man and woman can barely feed themselves, they ought to at least think twice about having a kid.  It's not cheap to raise them, even if you're in a country like the US where the government basically pays you to do it.  *grrr*