Those of you who follow "Spengler" on Asia Times Online are familiar with his argument coupling the birthrate with religious belief and the survival of a society. (An interesting correlation of this from an Episcopalian standpoint can be found here.)
It looks like he’s got some competition from the West Coast in the form of the Hoover Institute’s Mary Tedeschi Eberstadt in her recent article How the West Really Lost God. She’s not quite as entertaining as he is, but her research is of greater depth.
This line of thinking has some interesting implications for Evangelical churches, but some are putting it into practice.