Today's generation of fertile adults takes safe and effective contraception largely for granted. The thought that there might be ethical objections to its use within marriage may come as a surprise to many contemporary Christian couples. Yet for almost all of its history, the Christian church has viewed contraception with moral suspicion, if not outright antagonism. How is it that the pendulum has swung so far and so fast?
This File reflects on that journey, examines its legitimacy, and suggests we would do well to 'ask for the ancient paths'  to help guide us through contemporary complexities. CMF's recent publication Contraception - a guide to ethical usedescribes the mechanisms of action of today's contraceptives and explores how we should use them, but it does not explore whether we should use them. That is what this File aims to do.
How did we get here?
1. Theological trajectory - from Augustine to Anglicanism - contraception accepted
The Roman Catholic Church has remained officially opposed to artificial contraception, a stance rooted in Augustine's teaching that the chief purposes of marriage are the procreation and the education of children. It argues that the natural outcome of sex is the conception of a child and anything that interferes with this process is contrary to the way God created us and is therefore immoral.
However, both Augustine and later Aquinas, recognised the validity of 'rendering the marriage debt' - serving the needs of one's spouse out of loving concern for them (not out of personal lust) - a reflection of Paul's teaching that a man's body belongs not to him alone, but also to his wife and vice versa. Their main concern was to prohibit deviant sexual acts, ways of copulating in a 'base' way - so-called 'sins against nature' - in order to avoid procreation. 
In the twentieth century, the Roman Catholic Church broadened its teaching to include this unitive dimension of sex - strengthening mutual love and commitment within marriage - as a legitimate 'end', but crucially still holds today that the 'unitive' and 'procreative' aspects of sex should not be separated.
This teaching was reiterated by Pope Paul VI in his 1968 encyclical Humanae Vitae,  and in writings from Pope John Paul II, including a collection of essays entitled Theology of the Body.  Within this view, children are seen as a blessing and inheritance and voluntary childlessness as in conflict with God's purposes. However, where there are good reasons for spacing children, 'married people may then take advantage of the natural cycles immanent in the reproductive system and engage in marital intercourse only during those times that are infertile'. 
The Protestant Reformers generally maintained this stance and condemned birth control as a contravention of God's procreative purpose for marriage. The first signs of a change in attitude appeared in the late nineteenth century when fears that world population might outstrip world food resources fuelled an interest in family planning. In the twentieth century, theologian Karl Barth argued that raising children is not the primary aim of marriage and that sex in marriage stands alone and sufficient as a sign and seal of marital love and life-fellowship. He saw no absolute denial of the freedom to use birth control, so long as it is used with a sense of responsibility to God, not out of whim or impulse. According to Barth, men and women should therefore act freely and responsibly in deciding whether or not to have a child. 
Dietrich Bonhoeffer believed that 'marriage involves acknowledgement of the right of life that is to come into being, a right which is not subject to the disposal of the married couple'.  He taught that 'the right of nascent life is violated also in the case of a marriage in which the emergence of new life is consistently prevented, a marriage in which the desire for a child is consistently excluded.  However, he argued for a nuanced acceptance of contraception on pragmatic grounds - that to deny it completely, and instead to encourage abstinence, would undermine the physical nature of marital union such as could lead to marital tension and a weakening of the marital bond.
It was not until the Lambeth Conference of 1930 that the Anglican Church gave qualified ethical sanction to the use of birth control under certain limited conditions.  Thereafter, the gap between Protestant thought and official Roman Catholic teaching continued to widen. In 1968, the same year as the publication of Humanae Vitae, evangelical leaders in North America published A Protestant Affirmation on the Control of Human Reproduction.  It included a paper entitled A Christian View of Contraception which argued for contraception as 'the means of preventing the birth of unwanted children'.  Over the past 50 years, Protestant acceptance of contraception has steadily increased and today the overwhelming majority of evangelicals support the use of contraception in marriage. 
2. Philosophical trajectory - the triumph of autonomy - contraception encouraged
Respect for every person's desire for autonomy and self-determination has emerged as the prevailing ethical value in our society.  It is expressed through an emphasis on personal rights, and freedom of personal choice. This can be traced back to the Enlightenment philosopher John Stuart Mill: 'Over himself, over his body and mind, the individual is sovereign'.  Individual liberty is seen to include the right to have a child, and the right to choose when and how many children to have - what Ronald Dworkin has called the 'right of procreative autonomy'. 
3. Technological trajectory - creating a mindset - contraception embedded
Until the development of 'the pill', contraception relied on inconvenient and unreliable barrier methods. The advent of the oral contraceptive pill in 1961 changed everything. Somewhat ironically, 'its main inventor was a conservative Catholic who was looking for a cure for infertility and instead found a guarantee of it'.  Initially, it was prescribed mainly to married women with children, who felt their families were complete. That all changed in 1974 when family planning clinics were allowed to prescribe the pill to single women - a controversial decision at the time.
What followed was a global revolution. By 2000, 3.75 million women in the UK were estimated to be using the pill.  It is thought that 70% of all women in Britain have used the oral contraceptive at some stage in their lives. 
Within a few short years, contraception had become universally accepted. A generation of children grew up aware that their parents used contraception, and entered adulthood themselves believing that to use contraception is not only 'normal' but is to act responsibly.
4. Cultural trajectory - children as a 'lifestyle' choice - contraception celebrated
The 'Boomers' generation (those born between the mid 1940's and early 1960's) has been dubbed the 'me generation', and the 70's the 'me decade'.  The terms capture the aspirations to self-fulfilment and self-realisation that supposedly characterised that generation of young people. They grew up in, and helped shape a world that prized individual freedom of choice. It was a consumer-driven culture where reliable contraception had separated love-making from baby-making and offered 'sex without strings'. Today, casual sex and serial monogamy have become commonplace, facilitated in a digital age through mobile phone apps and online dating services.
These cultural changes have been accompanied by a shift in language from 'procreation' to 'reproduction'. A society that once understood conception as something largely under the mysterious control of a creator God now sees it as something very much under human control. One consequence is that children are seen less as gifts to be received gratefully and unconditionally, and more as products of human planning and ingenuity, to be chosen or rejected according to our preferences  - a lifestyle choice.
So, if this is where we have reached, from where did we start? What does the Bible say?
Sex as God intended
Sex is a gift from God who made us male and female - divinely designed 'twoness'.  Responsible stewardship of his gift is the governing ethic. Sex is reserved for marriage - the lifelong covenant commitment of one man and one woman. Marriage brings the two together as 'one flesh' and is a symbol of the love and union of Christ for, and with his bride, the Church. 
Sex is intended for procreation,  is a means of expressing and enhancing the unity of the marriage bond,  and is for pleasure and delight within married intimacy.  It is equally an important and legitimate expression of marital love between couples who have never been able to have children or whose child-bearing years have passed. This much is clear. But is there such a thing as morally-acceptable use of contraception and, if so, what defines it?
The creation mandate to procreate
Having created man and woman in his image, God blessed them and said, 'Be fruitful and increase in number, fill the earth and subdue it.'  This might be seen to run counter to any notion of contraception, but the procreation mandate was set in the wider context of the call to exercise dominion over the earth, working in and with nature to carry forward God's purposes. Humanity has been given a stewardship role, permission to intervene, to harness nature's forces in the pursuit of God's glory on earth. 
Hollinger argues that this at least opens the door of possibility to the ethical use of contraception, utilising non-natural means of contraception to work with nature just as we steward many dimensions of natural life through technology and human knowledge.  Others argue that conceiving children is not the product of a fallen world, pregnancy is not a disease requiring treatment and contraceptive technologies prevent the body from doing what God created it to do.  They commend instead natural family planning  (NFP): 'The woman's natural cycle makes it entirely possible to exercise control without recourse to contraception, and in a manner consistent with the way God has ordered sexuality',  working within the natural world to steward it.
Given the fallenness of our world, including nature, doctors frequently seek to alter nature in order to alleviate pain and suffering, in keeping with God's ultimate triumph over evil and suffering. Can the use of contraception be understood to fall within morally-acceptable limits of such interventions, or does it illicitly impede what would happen were nature allowed to run its course?
The purposes of sex
The initial purpose of sex is to consummate a marriage, and it remains the sign, seal and celebration of that union and oneness. Scripture uses 'one-flesh' language to describe this ultimate act and the exclusive relationship of mutual trust and self-giving that it signifies.  We could call this its symbolic purpose; it points to and represents Christ's love and commitment to his bride, the Church. 
Most obviously, both Genesis 1:28 and nature itself teach us that sex is inherently a procreative act. Of course, this does not mean that every act will result in a pregnancy - a woman is fertile for a relatively short part of her cycle - but the Catholic Church argues that in each sexual act one must be open to generation, by doing nothing unnatural that would prevent procreation. The most commonly-held Protestant view is that although one must be open to procreation because of sex's inherently procreative nature, there is scope for us as stewards of creation to intervene in the natural processes.
Sex as a means of expressing and strengthening love between married partners and for physical pleasure and delight has a unitive purpose. We are 'wired' for pleasure in that we are designed with certain organs that serve no other function than to mediate such pleasure. That we are created in such a way, as naturally to be able to enjoy sex without the inevitability of procreation, suggests that God intended it that way. If we were in any doubt about that, then the Song of Songs would seem to assure us it is so. 
So, can we legitimately set aside one purpose of sex (procreation) and yet enter fully into another purpose of sex (unity and delight)? Some argue that the multiple purposes of sex mean that the procreative dimension can be laid aside at certain points without qualm: 'Within marriage the sex act retains its meaning even when no possibility of pregnancy is present'. 
But not all agree. If we directly/artificially prevent the fertility of sex through contraception, but simply come together to express love in an intimate and pleasurable way, we do violence to the inherently procreative nature of sex, they suggest. Blackburn, for example, asks: 'Why do we assume that we can interfere with how God created marital intimacy and be unaffected?'  Pruss believes, 'For a genuine union between husband and wife, the sexual act cannot be modified in order to decrease its natural fruitfulness. The unity is not wrought by pleasure or a mingling of members, but through an organic union whose action is a striving at reproduction as an end, even if this end is unattainable at times'.  Impeding that organic union is considered inevitably to impede the spiritual unity of husband and wife.
'Onan  has the dubious honour of illustrating the Bible's one explicit example of contraception'.  His duty was to raise an heir to his brother's widow, Tamar, a practice later formalised in Levirate law.  However, he wilfully and repeatedly interrupted sex with Tamar, callously betraying her trust and denying his dead brother 'offspring'. For this, God punished him.
For centuries, the case of Onan has been used by the Catholic church to teach about the twin evils of contraception by coitus interruptus and masturbation. ,  The unusually explicit language used by the author and the severity of the punishment given, they believe, suggest that God's judgment was primarily upon Onan's contraceptive action.
The generally accepted interpretation among evangelicals today is that the reason for God's judgment upon Onan was his refusal to fulfil his obligation to his deceased brother, in keeping with the principle of Levirate marriage and inheritance, and that the passage has nothing to teach us about contraception.
Given the degree of uncertainty over the correct interpretation of the passage, we should not ask it to bear a greater weight of evidence for or against the use of contraception than it can.
Can we find an ethically acceptable contraceptive?
A detailed list of the pros and cons of contraception is included in the CMF booklet on the subject and should usefully be read alongside this File. 
For some who conclude artificial methods of family planning are not in keeping with the purposes of sex and the procreation mandate, Fertility Awareness Based Methods (FABMs) provide an ethically-acceptable form of contraception. These methods rely on collaboration with the natural rhythms of a woman's cycle, identifying in various ways those days during her cycle when she is likely to become pregnant. No direct interference with nature is involved and Catholic leaders have recognised the use of such methods as legitimate forms of family planning. It takes commitment and practice to use natural family planning effectively, but carefully followed these methods can be up to 99% effective. 
For others, FABMs are as ethically unacceptable as artificial forms of contraception. For such, the intention to avoid conceiving - a 'contraceptive mindset' - is seen to be at odds with the inherently procreative nature of sex.
Those who conclude that intervention by artificial means is morally acceptable face a perplexing array of choices, each with their own mode of action, pregnancy rate and potential side-effects. A comprehensive guide to the known mechanisms and effectiveness of contraceptives in current use is available from CMF.  But the defining question this cohort must answer before choosing any one of them is 'when does life begin'? The view taken of the status of the early embryo will determine those methods that are deemed ethically acceptable.
Within the wider Christian community, there are different views about the moral status of the embryo. CMF's starting point is the view that human life begins with fertilisation - a view justified both biologically and biblically. (For a detailed exploration of the supporting evidence for this view, see the CMF booklet: Contraception - a guide to ethical use.)
In this view, pregnancy commences with fertilisation of the egg, not implantation of the resulting embryo. Contraceptive methods that prevent the union of egg and sperm are therefore seen as ethically acceptable. Those that act post-fertilisation (whether pre- or post-implantation) are deemed ethically unacceptable. However, such tidy lines of demarcation are not simply drawn in practice. For example, much debate surrounds the mechanisms of action of hormonal contraceptives, something that the CMF guide explores in some detail. 
Towards a Conclusion
Sex is an act of love, with the power to nourish the marital relationship; it is also a procreative act. Whether a child is conceived or not it is still an act of procreation. Whether or not the relational bond is nourished, it is still an act of love. Both unitive and procreative purposes are equally intrinsic goods of sexual intercourse.
It is unnecessary to insist that these two goods are inseparable. Married sex does not have to generate a child in order for it to be a licit act of love. It is in the very nature of creation that a woman is fertile for only a few days in every cycle; yet nobody would suggest that a husband and wife should make love only on these days, or else deny by their actions the inherent procreative nature of sex. And if, in order to space their children, they are careful to avoid making love during the fertile days, they do not dishonour that inherent nature. Indeed, they honour it. And if such collaboration with the natural rhythms of nature in order to avoid producing a child is acceptable, then the intention to avoid conception is accepted. Harnessing this intention to ethically-acceptable forms of contraception  would also seem to be accepted in principle.
This is not to suggest that the use of contraception so as never to conceive - the wilful avoidance of childbearing altogether - is necessarily appropriate in marriage. This would deny the procreative nature of sex and the divine commission to be fruitful  (unless there is a medical reason to avoid pregnancy as, for instance, where the life of the woman might be endangered by it). But its use by mutual consent in planning a family, can be seen to fall within morally-acceptable limits of intervention in nature. Stewards of the gift of sex will see children, even when seemingly 'unplanned', as gifts from God to be welcomed and cherished. Morally acceptable contraception, will be seen as a means to help us serve God's creation mandate responsibly and wisely in a fallen world.
Rick Thomas combined medical practice and church leadership in Worcester for over forty years. He has an MA in Bioethics and Medical Law from St Mary's University and serves as a researcher in CMF's Public Policy department.