@winkio: LMAO! This totally sounds like my economics class back in college. ^_^ While I agree that economics definitely by definition cover all that, I don't think that you can really view everything as economics, because it's complete generalization. In the end it doesn't actually matter who's right here with economics, we are obviously thinking the same about general investment and payoff about having children. But you are right that it's influenced a lot more by society than I said in the first place.
I agree that having children is influenced a lot by society today. Even though psychology plays a role in this, psychology is also influenced by society. Most of it pretty much comes back to raw genetic programming and social programming where the latter can be altered by society. Since humans are self-aware and social animals, the social programming has probably a lot more influence in the end decision. Very interesting.