The First Things blog had an interesting post today (it includes links to some pretty interesting work on fertility and faith). It seems that the (few) Americans who are reproducing are those practicing their faith: "religion is a family affair."
From a secular point of view, there may be several causes of note. (1) Pregnancy and childbirth--as well as the care of a newborn, I'd add--invite one to fall back upon faith as an aide (AMEN); (2) contemplating the death of a child also intensifies the parents' need for God. Put positively, having children and "life together" give life such a sense of purpose and meaning that suddenly the question arises--could not every life have purpose and meaning? Creation itself?
And just as a thing cannot bring itself into existence, neither can it give itself meaning. Something--Someone--outside of it must ... exist.
Thomas Aquinas strikes again--this time in the midst of smelly diapers, sleepless nights, and the beauty of a child. There must be meaning; ergo there must be God. Faith from fertility.
(Oh, and then the sheer joy of meaning may even inspire more babies!" Fertility from faith.