Read Selfish Reasons to Have More Kids, Bryan Caplan. Most people are glad to have been born, most parents raise happy, healthy children in the industrialized world and in substantial parts of the world outside it, most children would rather have happy parents who spend time with them than more stuff and while you can effect how happy their childhood is you aren’t going to greatly effect their adult outcomes if you parent within the good enough to be allowed to adopt norms.
The best start in life is a start.