First of all, here is
Humanae Vitae at the Vatican website.
For the prophetic portion, you will probably want ilto look primarily at paragraph 17:
Consequences of Artificial Methods
17. Responsible men can become more deeply convinced of the truth of the doctrine laid down by the Church on this issue if they reflect on the consequences of methods and plans for artificial birth control. Let them first consider how easily this course of action could open wide the way for marital infidelity and a general lowering of moral standards. Not much experience is needed to be fully aware of human weakness and to understand that human beings—and especially the young, who are so exposed to temptation—need incentives to keep the moral law, and it is an evil thing to make it easy for them to break that law. Another effect that gives cause for alarm is that a man who grows accustomed to the use of contraceptive methods may forget the reverence due to a woman, and, disregarding her physical and emotional equilibrium, reduce her to being a mere instrument for the satisfaction of his own desires, no longer considering her as his partner whom he should surround with care and affection.
Finally, careful consideration should be given to the danger of this power passing into the hands of those public authorities who care little for the precepts of the moral law. Who will blame a government which in its attempt to resolve the problems affecting an entire country resorts to the same measures as are regarded as lawful by married people in the solution of a particular family difficulty? Who will prevent public authorities from favoring those contraceptive methods which they consider more effective? Should they regard this as necessary, they may even impose their use on everyone. It could well happen, therefore, that when people, either individually or in family or social life, experience the inherent difficulties of the divine law and are determined to avoid them, they may give into the hands of public authorities the power to intervene in the most personal and intimate responsibility of husband and wife.
One other point to bring up is that, prior to the 1930s, no Christian group supported the use of artificial contraception. The group that led the change was the Anglican Communion.
At their 1920 Lambeth Conference, they said the following in
Resolution 68:
We utter an emphatic warning against the use of unnatural means for the avoidance of conception, together with the grave dangers - physical, moral and religious - thereby incurred, and against the evils with which the extension of such use threatens the race.
At the 1930 Lambeth Conference, they changed their position (
Resolution 15):
…Nevertheless in those cases where there is such a clearly felt moral obligation to limit or avoid parenthood, and where there is a morally sound reason for avoiding complete abstinence, the Conference agrees that other methods may be used, provided that this is done in the light of the same Christian principles. The Conference records its strong condemnation of the use of any methods of conception control from motives of selfishness, luxury, or mere convenience.
By 1958, Lambeth had gone as far as this (
Resolution 115):
The Conference believes that the responsibility for deciding upon the number and frequency of children has been laid by God upon the consciences of parents everywhere; that this planning, in such ways as are mutually acceptable to husband and wife in Christian conscience, is a right and important factor in Christian family life and should be the result of positive choice before God.
If something is wrong in the area of moral theology, is it not
always wrong?