"Throughout the world, the religious tend to have more children, irrespective of age, education or wealth. "Secular" Europe is no exception. In an analysis of European data from ten west European countries in the period 1981-2004 I found that next to age and marital status, a woman's religiosity was the strongest predictor of her number of offspring."There's a number of obvious reasons why this is so. Religious people are more likely to get married than non-religious people. Moreover, all other things being equal, they do so younger; stay together longer; and are less likely to use contraception or have abortions. So they have more babies.
In the case of the United States, Kaufmann argues that breeding is responsible for around 75% of the growth in Evangelical Protestantism in recent years. He suggests that a similar trend could be felt in Europe too:
"Over the longue durée, the fundamentalist component of Europe's population may begin to increase for the same demographic reasons as in America. The diversity of religious groups in Europe will guarantee a separation of religion and state, but this cannot protect secular public policies from being eroded by a coalition of religious groups who have agreed to submerge their differences. Religious lobbyists, couching their claims in the rhetoric of relativism and diversity, will ask why the secular point of view on issues like abortion, blasphemy, pornography and evolution is the only one taught, aired or "respected."I'm not sure about some of Kaufmann's conclusions. Establishing that the religious have more children is straightforward enough - but since he's already pointed out that it is religiosity as such that has this effect, it can't follow that this should necessarily translate into a growth in 'fundamentalism'. Nor does it explain the increasing tendency for the religious to become politicised in the first place.
Still, anyway you slice it, this demographic phenomenon has to be a problem for people who favour the Dawkins-style monist application of evolutionary biology to all matters of human conduct, surely?