"Many people assert that it is absolutely necessary for population growth to be radically reduced everywhere or at least in certain nations. They say this must be done by every possible means and by every kind of government intervention. Hence this Council exhorts all to beware against solutions contradicting the moral law, solutions which have been promoted publicly or privately, and sometimes actually imposed. For in view of the inalienable human right to marry and beget children, the question of how many children should be born belongs to the honest judgement of parents. The question can in no way be committed to the decision of government. Now since the judgement of the parents supposes a rightly formed conscience, it is highly important that everyone be given the opportunity to practice upright and truly human responsibility. This responsibility respects the divine law and takes account of circumstances and the times. It requires that educational and social conditions in various places be changed for the better, and especially that religious instruction or at least full moral training be provided. Human beings should also be judiciously informed of scientific advances in the exploration of methods by which spouses can be helped in arranging the number of their children. The reliability of these methods should be adequately proven and their harmony with the moral order should be clear."
-Vatican Council II (GS, 87).