There are two documents on the site under this heading:
Birth control has been debated among Christians for centuries; until the early 1900s there was a more or less universal rejection of artificial contraception. Societal changes in the 20th century led to breaks with this tradition in some churches; the Roman Catholic Church remains opposed to artificial contraception but accepts natural means of family planning. Some other Christian groups also continue to reject artificial contraception, with varying stances on natural methods.
For Christians, the Bible is an important - in some traditions the only important - source of teaching. This section of the NFP Information Site examines the Biblical background to a Chrstian rejection of contraception.
First let it be said that nowhere in Scripture will you find a blatant statement 'contraception is wrong', although:
What you do find in Scripture, though, is a developing theme of the sexual relationship between man and woman and its meanings: the question, then, is whether contraception falls in line with this Scriptural understanding, or whether it cuts across it.
Let's start at the beginning - Genesis. Gen 1:26-28 deals with God's decision to create humankind, in his own image, to have dominion over the earth, and to be fruitful: as he himself is the Creator they too are to be creators through His commission. Term definition: they are to be procreative: creative in co-operation with God. It is in the nature of their own creation that they themselves shall be creative: and one way in which they image God as Creator is through that creative potential.
Gen 2: 21-24 puts this in a context. There is a relationship between man and woman: it is not just a question of difference but of complementarity. Together they form one flesh, bone of bone, flesh of flesh. Together they are a true unity: their relationship is unitive, building on and building up the unity between them. One plus one makes something rather different from two.
So right from the start of Scripture there is an imagery of man and woman, formed as procreative, and formed in unity one with the other. The imagery is plainly sexual: it is through sexual intercourse that procreation takes place, and it is in sexual intercourse that man and women become most physically one flesh.
Let's move on. I'm not going to list texts here, but it must be reasonably clear that the development of the relationship between God and His people is shown in acts of marriage and the conception of children. Sarah bears a son; Jacob engenders sons in profusion as his wives and their servants vie to show the blessing of the Lord; the comings of prophets and heroes of Israel are foretold by angels and in a man and his wife having a child, often when they are outside the usual childbearing age. Marriage becomes a monogamous thing. The Song of Songs is about the love of humankind for God, and about the love of man for woman - neither aspect alone can really describe what the Song means. Hosea and his wife are signs of the broken and mendable relationship between God and humankind. Marriage is certainly something more than a mere social construct - it is a sign of some sort.
In the Gospels, Christ speaks and acts about marriage. He answers questions with a clear statement that marriage forms an unbreakable unity. His first public miracle is at a wedding ceremony: the first open sign that God has joined his people is at the time when a man joins his wife. He makes it clear too, though, that marriage is for earth rather than in the resurrection: it is a sign for our times.
Paul (Eph 5:21-32) states what this sign is. It is the sign of the love between Christ and the Church - the unity which, because of Calvary, cannot be broken. This is what the unity of man and wife in becoming one flesh has meant throughout the ages: the fulfilment of the love between God and His People.
From all this we can draw two principal meanings of marriage:
Both of these meanings are equally applicable to the sexual expression of marriage - indeed it is only through the sexual expression that the two meanings are most fully expressed in becoming 'one flesh'.
So onto the question: where does contraception fit with this? The idea of birth control is to limit the procreativity of marriage (I'm making no statement here at all about the position of contraception outside marriage). That is not necessarily a problem: whilst the instruction to be fruitful and multiply cannot be ignored, it can be interpreted in line with needs and indeed capacity. What would be a problem would be a means of birth control which acted by removing one of the meanings of marriage from the sexual expression of marriage - these two meanings cannot (in faith with the Scriptural meanings of marriage) be put apart, any more than husband and wife can be put apart, or than God the Creator and God the Son in relationship with the Church can be put apart.
Where something is changed in the sexual act, or something is changed in one or other of the spouses to alter the potential of the sexual expression of marriage, though, something quite different is happening. The decision has been taken that the innate link between the procreative meaning of intercourse and its unitive meaning can be overridden or ignored; the sexual act is no longer all it is designed to be. It falls short. And that is one of the definitions of the word 'sin'.
Contraception, though, does exactly that: all contraceptive methods change in some way the nature of the spouses. Barrier methods close the spouses' bodies to each other; chemical methods change their bodies. On this basis, we can see that contraception is sinful, and out of line with a Scriptural understanding of marriage.
Two notes at the end: