Even people who are rubbish parents in the first world produce many children who are productive and happy and help ease the problems of those who are lacking in the world.
The difference between first world and third world is in the third world they value family and tribe, while we mostly just value the individual. Yeah, that makes us more seflish, we just value ourselves. Maybe most importantly though, it is economically beneficial to have a large family in the poorer areas, they can have their children help out around, and there isn't that much cost for having a child if things go bad ( the child just dies or is sold to slavery or etc).
A lot of the problems today, in first world nations, is the lack of those who can provide education and resources to their children having children. So instead, you have old people living longer and longer, hoarding their wealth for themselves and when they die it goes to a few other people who are hoarding their wealth for themsevles.
JM
Jon Miller