The proof of the thesis, however, lies in the fact that governments often pay married couples to have children. Such policies have not, alas, been successful. It was with great amusement that in this, as in so many other matters, we have followed the Romans:
It was next proposed to relax the Papia Poppaea law, which Augustus in his old age had passed subsequently to the Julian statutes, for yet further enforcing the penalties on celibacy and for enriching the exchequer. And yet, marriages and the rearing of children did not become more frequent, so powerful were the attractions of a childless state. - Tacitus, The Annals, 3.25
Pat Buchanan insists that historians will one day call the birth control pill the suicide tablet of the west. In this, as in so many other matters, he is probably correct, but the simple fact is that those who do not wish to procreate, will find means to avoid it. The Romans did not need fancy pills to be overrun by the German barbarians.
On the other hand, knowledge of the means of contraception used by the Romans did not prevent the early Church from being fertile and multiplying. So there is a definite bright side here, only, it probably comes on the other side of the decline and fall of our present civilization.