Contraception is nothing new. Jason Evert shared with me that, “history records people using various methods of birth control four thousand years ago. Ancient people swallowed potions to cause temporary sterility; they used linens, wool, or animal skins as barrier methods; they fumigated the uterus with poison to keep it from bearing life. The Romans practiced contraception, but the early Christians stood out from the pagan culture because they refused to use it.”
As many now know, all of Christendom was unanimously against the use of contraception until the year 1930. It was during that year that the Anglican church in its seventh Lambeth conference permitted the use of birth control under limited circumstances.
Since that time the entire Protestant world has collapsed on this issue. Some even see contraception as virtuous, such as The Presbyterian Church (USA) who “full and equal access to contraceptive methods.” and have said that “contraceptive services are part of basic health care.” 
Many Protestants aren’t aware of how vociferously the Protestant reformers spoke out against contraception.
Here are three quotes which reference Genesis 38, which recounts the story of Onan, who “went in to his brother’s wife [and] spilled the semen on the ground” (9), a sin which God “slew” him for.
(I want to make it clear that these three quotations don’t necessarily represent the Catholic position, which I’ll post at the bottom).
“Onan must have been a malicious and incorrigible scoundrel. This is a most disgraceful sin. It is far more atrocious than incest or adultery. We call it unchastity, yes, a Sodomitic sin. For Onan goes into her; that is, he lies with her and copulates, and when it comes to the point of insemination, spills the semen, lest the woman conceive. Surely at such a time the order of nature established by God in procreation should be followed.” (Luther’s Works 7, 20-21)
“Onan, though he consented to marry the widow, yet to the great abuse of his own body, of the wife he had married and the memory of his brother that was gone, refused to raise up seed unto the brother. Those sins that dishonour the body are very displeasing to God, and the evidence of vile affections. Observe, the thing which he did displeased the Lord – And it is to be feared, thousands, especially single persons, by this very thing, still displease the Lord, and destroy their own souls.”
“I will content myself with briefly mentioning this, as far as the sense of shame allows to discuss it. It is a horrible thing to pour out seed besides the intercourse of man and woman. Deliberately avoiding the intercourse, so that the seed drops on the ground, is doubly horrible. For this means that one quenches the hope of his family, and kills the son, which could be expected, before he is born.
The wickedness is now as severely as is possible condemned by the Spirit, through Moses, that Onan, as it were, through a violent and untimely birth, tore away the see of his brother out the womb, and as cruel and shamefully was thrown on the earth. Moreover he thus has, as much as was in his power, tried to destroy a part of the human race. When a woman in some way drives away the seed out the womb, through aids, then this is rightly seen as an unforgivable crime. Onan was guilty of a similar crime, by defiling the earth was his seed, so that Tamar would not receive a future inheritor.” (Commentary on Genesis).
The Catholic Church
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. 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:
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. (CCC 2370).