There are three questions which come up in relation to the growth of religious movements, particularly the Christian faith. How would you answer each of these?
a. Why is Islam growing in the UK and in the world at the moment?
b. What was the primary reason for the growth of the early church?
c. Why in the West do conservative churches generally resist the decline that affects more liberal ones?
Now these are big questions, and the answers are bound to be complex. But generally in answer to (a) most people will reach for an explanation around the rise of fundamentalism and a global rejection of Western liberal values. In answer to (b) many will think about the cultural and religious distinctiveness of the early Christian movement, and its appeal in relation to the cruelty and fatalism of much pagan religion. And in answer to (c) many will reach for ideas of commitment and discipleship which resist the corrosion of modern individualist and consumerist culture.
But there is a good case to be made that all three have the same explanation: childbirth.