The Church is coherent with herself when she considers recourse to the infecund periods to be licit, while at the same time condemning, as being always illicit, the use of means directly contrary to fecundation, even if such use is inspired by reasons which may appear honest and serious. In reality, there are essential differences between the two cases; in the former, the married couple make legitimate use of a natural disposition; in the latter, they impede the development of natural processes. It is true that, in the one and the other case, the married couple are concordant in the positive will of avoiding children for plausible reasons, seeking the certainty that offspring will not arrive; but it is also true that only in the former case are they able to renounce the use of marriage in the fecund periods when, for just motives, procreation is not desirable, while making use of it during infecund periods to manifest their affection and to safeguard their mutual fidelity. By so doing, they give proof of a truly and integrally honest love.

 
Grave Consequences of Methods of Artificial Birth Control

17. Upright men can even better convince themselves of the solid grounds on which the teaching of the Church in this field is based, if they care to reflect upon the consequences of methods of artificial birth control. Let them consider, first of all, how wide and easy a road would thus be opened up towards conjugal infidelity and the general lowering of morality. Not much experience is needed in order to know human weakness, and to understand that men-especially the young, who are so vulnerable on this point-have need of encouragement to be faithful to the moral law, so that they must not be offered some easy means of eluding its observance. It is also to be feared that the man, growing used to the employment of anticonceptive practices, may finally lose respect for the woman and, no longer caring for her physical and psychological equilibrium, may come to the point of considering her as a mere instrument of selfish enjoyment, and no longer as his respected and beloved companion.

Let it be considered also that a dangerous weapon would thus be placed in the hands of those public authorities who take no heed of moral exigencies. Who could blame a government for applying to the solution of the problems of the community those means acknowledged to be licit for married couples in the solution of a family problem? Who will stop rulers from favoring, from even imposing upon their peoples, if they were to consider it necessary, the method of contraception which they judge to be most efficacious? In such a way men, wishing to avoid individual, family, or social difficulties encountered in the observance of the divine law, would reach the point of placing at the mercy of the intervention of public authorities the most personal and most reserved sector of conjugal intimacy.