According to Longman:
“[I]n countries rich and poor, under all forms of government, birth rates are declining across the globe. But they are declining least among those adhering to strict religious codes and literal belief in the Bible, the Torah, or the Koran.”Kaufman's book is titled, Shall the Religious Inherit the Earth?: Demography and Politics in the Twenty-First Century. The product description of the book says this:
“Indeed, the pattern of human fertility now fits this pattern: the least likely to procreate are those who profess no belief in God; those who describe themselves as agnostic or simply spiritual are only somewhat slightly less likely to be childless. Moving up the spectrum, family size increases among practicing Unitarians, Reform Jews, mainline Protestants and ‘cafeteria’ Catholics, but the birthrates found in these populations are still far below replacement levels.
Only as we approach the realm of religious belief and practice marked by an intensity we might call, for lack of a better word, ‘fundamentalism,’ do we find pockets of high fertility and consequent rapid population growth.”
“When confronted with the fact that they are being outbred, secularists often respond that many if not most children born into highly religious families will grow up to reject the faith of their fathers,” but “[a]mong fundamentalist families, it turns out, the apple does not fall far from the tree. And the more demanding the faith, the more this rule applies. Only five percent of children born to the most conservative Amish, for example, move on to other faiths or lifestyles.”
“Richard Dawkins and Christopher Hitchens have convinced many western intellectuals that secularism is the way forward, but most people don’t read their books before deciding whether to be religious. Instead, they inherit their faith from their parents, who often inoculate them against the elegant arguments of secularists.Vjtorley points out the irony in these predictions that believers will swamp non-believers by out-reproducing them - a purely Darwinian strategy for biological success. He also believes that the secular elites are aware of this, but are in a bind, because they have only three options for combatting the rising percentage of believers. They can have more children themselves, they can seek to undercut the religious beliefs of believers' children, and they can prevent believers from having children.
And what no one has noticed is that far from declining, the religious are expanding their share of the population; in fact, the more religious people are, the more children they have. The cumulative effect of immigration from religious countries and religious fertility will be to reverse the secularization process in the West. Not only will the religious eventually triumph over the non-religious, but it is those who are the most extreme in their beliefs who have the largest families.”
The first is anathema to most secularists because they're generally among those who believe the earth is over-populated as it is, and that everyone should limit themselves to just two children.
That leaves the second and third options, and vjtorley lays out the measures that he thinks we might soon see advanced which, deliberately or not, will have the effect of diminishing the strength of religious belief both here and abroad.
Read what he thinks lies in store for religious folk in both the near and middle future at the link. It's both fascinating and chilling.