Consider once again the remarkable vibrancy of Christian practice across the West in the years following the Second World War — the religious boomlet much remarked upon by sociologists of the time, and still within living memory of some today. That boomlet was pan-Western in scope. It applied to the vanquished as well as the victorious, the neutral as well as everyone else, the economically devastated as well as the prosperous. So what explains it?

To study the timeline is to see that the years of postwar religiosity coincided precisely with another much-studied phenomenon of those years: the baby boom. Across the Western world, the war was followed by an increase in marriage and babies. Is it not just common sense to think that the baby boom and the religious boom went hand in hand — indeed, that each trend powered and reinforced the other in a way highly suggestive of this overlooked aspect of what makes Christianity tick?

In brief, the idea is that something about families (and in all likelihood, more than one "something") increases the likelihood that people will go to church, for all sorts of reasons: because they will seek out a like-minded moral community in which to situate their children; because the experience of birth, of simply being mothers and fathers, transports some into a religious frame of mind; because the idea of loving someone enough to die for him arguably comes more easily to the parents of the world than to mortals who do not know that primal bond. In these ways as in others, one can argue, communal life within the family might incline people toward religion generally, and specifically toward Christianity — a religion that begins, after all, with a baby and a Holy Family, and whose revolutionary notion that a valid marriage requires consent of both parties remains one of the most family-friendly human rights innovations of all time.