Aaron yesterday suggested children may be an expensive luxury. Dude, there’s good science backed up by badass mathematical analysis to support that suggestion.
One of the puzzles of demography has long been that as societies get richer, they tend to have lower birth rates. This seems evolutionarily counter-intuitive. As you get richer, you ought to be able to support more offspring. But it turns out that as we get richer, we end up needing to shower the younguns with more stuff, so as we get richer it gets paradoxically more expensive to add offspring. So as societies industrialize, their birth rates go down. The math involves allometric scaling laws that also match energy flow-body size patterns in critters. Turns out that the economics here can also be modelled as energy flow through the societal system.