When you live in a society dominated by agriculture children are an asset.  When you live in an industrial&#x2F;service based society like our own children are a cost.  So generally speaking, most people have fewer children.  As the world develops the trend continues.  China is probably a data anomaly because of it&#x27;s one child policy... however if it had not had it, i&#x27;d be willing to bet you could watch the trend.<p>I&#x27;ll just throw this out there, I pay $1600 a month for daycare.  It&#x27;s the reason I have 1 kid, and waiting before having a second.  Throw into the mix better birth control tech&#x2F;education&#x2F;use, and this kind of restraint is possible.