Here is an answer from Fr. William Saunders:
In explaining the Church’s teaching about artificial birth control, many people mistakenly think that this teaching is relatively new, something which occurred with “Humanae Vitae” in 1968.
Of course, Fr. Saunders starts with the story of Onan:
In Genesis, we find the story of Onan, the second son of Judah, who married Tamar, the widow of his older brother, Er. (The Levirate law of Judaism prescribed that if the older brother died the next oldest, single brother would marry his widow to preserve the family line.) The Bible reads, “Onan, however, knew that the descendants would not be counted as his; so whenever he had relations with his brother’s widow, he wasted his seed on the ground to avoid contributing offspring for his brother. What he did greatly offended the Lord and the Lord took his life” (cf Dt 38:1ff.) Here is a basic form of contraception withdrawal end clearly a sin in the eyes of God.
Advocates of artificial birth control try to say that Onan’s real sin was violating duty to his brother or some other sin, sometimes citing Rabbinical teachings.
However, it is defined Catholic teaching that “dissent” from an official Church interpretation of Scripture is heresy: yes, you can find *more* than what the Church has defined. But if, as in this case, the Church says, “Onan’s sin is contraception,” you can’t say, “No, it’s not.”
He moves on to the historical use of contraception in the ancient world:
History further illuminates the Church’s position on this subject. Anthropological studies show that means of artificial birth control existed in antiquity. Medical papyri described various contraceptive methods used in the year 2700 B.C. and in Egypt in the year 1850 B.C. Soranos (98-139 A.D.), a Greek physician from Ephesus, described 17 medically approved methods of contraception. Also at this time, abortion and infanticide were not uncommon practices in the Roman Empire.
Of course, as I often pointed out, we should read Exodus 1 in this context:
Then a new king, who knew nothing of Joseph 4 , came to
power in Egypt. He said to his subjects, “Look how numerous and powerful
the Israelite people are growing, more so than we ourselves! Come, let us
deal shrewdly with them to stop their increase; otherwise, in time of war they
too may join our enemies to fight against us, and so leave our country.” (Exodus
Then he discusses the condemnations of “pharmakeia,” or “witchcraft,” or “potion-making,” which is usually listed as a sexual sin:
The early Christian community upheld the sanctity of marriage, marital love and human life. In the New Testament, the word “pharmakeia” appears, which some scholars link to the birth control issue. “Pharmakeia” denotes the mixing of potions for secretive purposes, and from Soranos and others, evidence exists of artificial birth control potions. Interestingly, “Pharmakeia” is sometimes translated as “sorcery?” in English. In three passages in which “pharmakeia” appears, other sexual sins are also condemned: lewd conduct, impurity, licentiousness, orgies “and the like” (e.g. Gal 5:19-21). This evidence highlights that the early Church condemned anything which violated the integrity of marital love.
“Thou shalt do no murder; thou shalt not commit adultery”; thou shalt not commit
sodomy; thou shalt not commit fornication; thou shalt not steal; thou shalt not
use magic; thou shalt not use philtres; thou shalt not procure abortion, nor
commit infanticide; “thou shalt not covet thy neighbor’s goods”
2370 Periodic continence, that is, the methods of birth regulation based on self-observation and the use of infertile periods, is in conformity with the objective criteria of morality.158 These methods respect the bodies of the spouses, encourage tenderness between them, and favor the education of an authentic freedom. In contrast, “every action which, whether in anticipation of the conjugal act, or in its accomplishment, or in the development of its natural consequences, proposes, whether as an end or as a means, to render procreation impossible” is intrinsically evil:159
“Thus the innate language that expresses the total reciprocal self-giving of husband and wife is overlaid, through contraception, by an objectively contradictory language, namely, that of not giving oneself totally to the other. This leads not only to a positive refusal to be open to life but also to a falsification of the inner truth of conjugal love, which is called upon to give itself in personal totality. . . . The difference, both anthropological and moral, between contraception and recourse to the rhythm of the cycle . . . involves in the final analysis two irreconcilable concepts of the human person and of human sexuality.”160
. . .
2399 The regulation of births represents one of the aspects of responsible fatherhood and motherhood. Legitimate intentions on the part of the spouses do not justify recourse to morally unacceptable means (for example, direct sterilization or contraception).
53. And now, Venerable Brethren, we shall explain in detail the evils opposed to each of the benefits of matrimony. First consideration is due to the offspring, which many have the boldness to call the disagreeable burden of matrimony and which they say is to be carefully avoided by married people not through virtuous continence (which Christian law permits in matrimony when both parties consent) but by frustrating the marriage act. Some justify this criminal abuse on the ground that they are weary of children and wish to gratify their desires without their consequent burden. Others say that they cannot on the one hand remain continent nor on the other can they have children because of the difficulties whether on the part of the mother or on the part of family circumstances .
54. But no reason, however grave, may be put forward by which anything intrinsically against nature may become conformable to nature and morally good. Since, therefore, the conjugal act is destined primarily by nature for the begetting of children, those who in exercising it deliberately frustrate its natural power and purpose sin against nature and commit a deed which is shameful and intrinsically vicious.
55. Small wonder, therefore, if Holy Writ bears witness that the Divine Majesty egards with greatest detestation this horrible crime and at times has punished it with death. As St. Augustine notes, “Intercourse even with one’s legitimate wife is unlawful and wicked where the conception of the offspring is prevented. Onan, the son of Judah, did this and the Lord killed him for it.”
56. Since, therefore, openly departing from the uninterrupted Christian tradition some recently have judged it possible solemnly to declare another doctrine regarding this question, the Catholic Church, to whom God has entrusted the defense of the integrity and purity of morals, standing erect in the midst of the moral ruin which surrounds her, in order that she may preserve the chastity of the nuptial union from being defiled by this foul stain, raises her voice in token of her divine ambassadorship and through Our mouth proclaims anew: any use whatsoever of matrimony exercised in such a way that the act is deliberately frustrated in its natural power to generate life is an offense against the law of God and of nature, and those who indulge in such are branded with the guilt of a grave sin.
57. We admonish, therefore, priests who hear confessions and others who have the care of souls, in virtue of Our supreme authority and in Our solicitude for the salvation of souls, not to allow the faithful entrusted to them to err regarding this most grave law of God; much more, that they keep themselves immune from such false opinions, in no way conniving in them. If any confessor or pastor of souls, which may God forbid, lead the faithful entrusted to him into these errors or should at least confirm them by approval or by guilty silence, let him be mindful of the fact that he must render a strict account to God, the Supreme Judge, for the betrayal of his sacred trust, and let him take to himself the words of Christ: “They are blind and leaders of the blind: and if the blind lead the blind, both fall into the pit.
58. As regards the evil use of matrimony, to pass over the arguments which are shameful, not infrequently others that are false and exaggerated are put forward. Holy Mother Church very well understands and clearly appreciates all that is said regarding the health of the mother and the danger to her life. And who would not grieve to think of these things? Who is not filled with the greatest admiration when he sees a mother risking her life with heroic fortitude, that she may preserve the life of the offspring which she has conceived? God alone, all bountiful and all merciful as He is, can reward her for the fulfillment of the office allotted to her by nature, and will assuredly repay her in a measure full to overflowing.
. . .
61. However, they should take care lest the calamitous state of their external affairs should be the occasion for a much more calamitous error. No difficulty can arise that justifies the putting aside of the law of God which forbids all acts intrinsically evil. There is no possible circumstance in which husband and wife cannot, strengthened by the grace of God, fulfill faithfully their duties and preserve in wedlock their chastity unspotted. This truth of Christian Faith is expressed by the teaching of the Council of Trent. “Let no one be so rash as to assert that which the Fathers of the Council have placed under anathema, namely, that there are precepts of God impossible for the just to observe. God does not ask the impossible, but by His commands, instructs you to do what you are able, to pray for what you are not able that He may help you.”
. . .
65. All of which agrees with the stern words of the Bishop of Hippo in denouncing those wicked parents who seek to remain childless, and failing in this, are not ashamed to put their offspring to death: “Sometimes this lustful cruelty or cruel lust goes so far as to seek to procure a baneful sterility, and if this fails the fetus conceived in the womb is in one way or another smothered or evacuated, in the desire to destroy the offspring before it has life, or if it already lives in the womb, to kill it before it is born. If both man and woman are party to such practices they are not spouses at all; and if from the first they have carried on thus they have come together not for honest wedlock, but for impure gratification; if both are not party to these deeds, I make bold to say that either the one makes herself a mistress of the husband, or the other simply the paramour of his wife.”
. . .
71 Furthermore, Christian doctrine establishes, and the light of human reason makes it most clear, that private individuals have no other power over the members of their bodies than that which pertains to their natural ends; and they are not free to destroy or mutilate their members, or in any other way render themselves unfit for their natural functions, except when no other provision can be made for the good of the whole body.
Mater et Magistra:
191. But granting this, We must nevertheless state most emphatically that no statement of the problem and no solution to it is acceptable which does
violence to man’s essential dignity; those who propose such solutions base them on an utterly materialistic conception of man himself and his life.
. . .
193. We must solemnly proclaim that human life is transmitted by means of
the family, and the family is based upon a marriage which is one and indissoluble and, with respect to Christians, raised to the dignity of a
sacrament. The transmission of human life is the result of a personal and
conscious act, and, as such, is subject to the all-holy, inviolable and immutable laws of God, which no man may ignore or disobey. He is not
therefore permitted to use certain ways and means which are allowable in the propagation of plant and animal life.
194. Human life is sacred—all men must recognize that fact. From its very inception it reveals the creating hand of God. Those who violate His laws not only offend the divine majesty and degrade themselves and humanity, they also sap the vitality of the political community of which they are members.
. . .
196. Genesis relates how God gave two commandments to our first parents: to
transmit human life—”Increase and mutliply” (44)—and to bring nature into their service—”Fill the earth, and subdue it.” (45) These two commandments are complementary .
197. Nothing is said in the second of these commandments about destroying nature. On the contrary, it must be brought into the service of human life.
. . .
199. A provident God grants sufficient means to the human race to find a dignified solution to the problems attendant upon the transmission of human life. But these problems can become difficult of solution, or even insoluble, if man, led astray in mind and perverted in will, turns to such means as are opposed to right reason, and seeks ends that are contrary to his social nature and the intentions of Providence.
Human procreation requires on the part of the spouses responsible collaboration with the fruitful love of God; the gift of human life must be actualized in marriage through the specific and exclusive acts of husband and wife, in accordance with the laws inscribed in their persons and in their union.
From Evangelium Vitae:
13. . . . It may be that many people use contraception with a view to excluding the subsequent temptation of abortion. But the negative values inherent in the “contraceptive mentality”—which is very different from responsible parenthood, lived in respect for the full truth of the conjugal act—are such that they in fact strengthen this temptation when an unwanted life is conceived. Indeed, the pro-abortion culture is especially strong precisely where the Church’s teaching on contraception is rejected. Certainly, from the moral point of view contraception and abortion are specifically different evils: the former contradicts the full truth of the sexual act as the proper expression of conjugal love, while the latter destroys the life of a human being; the former is opposed to the virtue of chastity in marriage, the latter is opposed to the virtue of justice and directly violates the divine commandment “You shall not kill”.
But despite their differences of nature and moral gravity, contraception and abortion are often closely connected, as fruits of the same tree. It is true that in many cases contraception and even abortion are practised under the pressure of real-life difficulties, which nonetheless can never exonerate from striving to observe God’s law fully. Still, in very many other instances such practices are rooted
in a hedonistic mentality unwilling to accept responsibility in matters of sexuality, and they imply a self-centered concept of freedom, which regards procreation as an obstacle to personal fulfilment. The life which could result from a sexual encounter thus becomes an enemy to be avoided at all costs, and abortion becomes the only possible decisive response to failed contraception.
The close connection which exists, in mentality, between the practice of contraception and that of abortion is becoming increasingly obvious. It is being demonstrated in an alarming way by the development of chemical products, intrauterine devices and vaccines which, distributed with the same ease as contraceptives, really act as abortifacients in the very early stages of the development of the life of the new human being.
91. . . . It is therefore morally unacceptable to encourage, let alone impose, the use of methods such as contraception, sterilization and abortion in order to regulate births.
Here’s a case by Fr. Brian Harrison on the infallible formulation of Humanae Vitae.
Here’s a reprint of an article from L’Osservatore Romano which explains why our obedience is not limited to infallible declarations.