The intersection of Christianity and abortion has a long and complex history though there is no mention of abortion in the Christian Bible. At different times, early Christians held different beliefs about abortion, and most contemporary Christian denominations have nuanced positions, thoughts and teachings about abortion. More generally, some Christian denominations can be considered pro-life while others may be considered pro-choice. Additionally, there are sizable minorities in all denominations that disagree with their denomination's stance on abortion.
Generally, early Christian fathers strongly condemned abortion outright, including: Basil , Jerome , John Chrysostom , Athenagoras , Clement of Alexandria , Tertullian , Hippolytus , and Minicius Felix . Between the 2nd Century AD to 4th Century AD, the Didache, Barnabas and the Apocalypse of Peter strongly condemned and outlawed abortion. For example, the Didache states "Thou shalt not murder a child by abortion." (2:2) Pope Stephen V has stated "If he who destroys what is conceived in the womb by abortion is a murderer, how much more is he unable to excuse himself of murder who kills a child even one day old." Pope Sixtus V enforced excommunication for those who performed abortions at any stage of gestation. Furthermore, the Church's official magisterial position has always been against abortion and has remained so throughout history.
Scholars generally agree that abortion was performed in the classical world, but there is disagreement regarding the frequency and which cultures influenced early Christian thought on abortion. Currently, there is a disagreement among scholars as to whether the concept of delayed ensoulment, inherited from both Judaic and Greek traditions, raised exceptions to the classification of abortion as murder. As background, some very early Christians believed, as the Greeks did, in delayed ensoulment, or that a fetus does not have a soul until quickening. St. Augustine believed that the soul of a fetus at an early stage is not present. St. Thomas Aquinas, Pope Innocent III, and Pope Gregory XIV also believed that a fetus does not have a soul until "quickening," or when the fetus begins to kick and move. Despite the scientific opinion of the time concerning the time of ensoulment, which would make early abortion, though gravely sinful, distinct from homicide, the condemnation of abortion remained unchanged.
From the 4th to 16th Century AD, Christian philosophers had varying stances on abortion. Under the first Christian Roman emperor Constantine, there was a relaxation of attitudes toward abortion. However, most scholars agree that these people still believed that abortion was always a sin. For example, Pope Stephen V and Pope Sixtus V opposed abortion at any stage of pregnancy.
Abortion, direct infanticide and exposing a newborn to the elements so as to possibly bring about its death were often used when a pregnancy or birth resulted from sexual licentiousness practiced by "pagans" and included infidelity, prostitution and incest. These contexts cannot be separated from abortion in early Christianity.
The Catholic Church opposes procedures whose purpose is to destroy an embryo or fetus. The Church today firmly holds that "the first right of the human person is his life" and that life is assumed to begin at fertilization. The equality of all human life is fundamental and complete, any discrimination is evil. Therefore, even when a woman's life appears jeopardized, choosing her life over her child's is no less discrimination between two lives - and therefore morally unacceptable. Accordingly, an abortion to save the life of the mother is unnacceptable. The Church's opposition to abortion is also based on its belief about the destination of unbaptised souls and the possibility of them being in Limbo.
Catholics who procure or participate in an abortion are subject to ipso facto latae sententiae (automatic, literally by that very fact the sentence is incurred) excommunication under Canon law, provided that the person knows of the penalty at the time the abortion occurs. The Catholic Church also considers the destruction of any embryo to be equivalent to abortion. Papal Encyclical, Humanae Vitae, states that: "We are obliged once more to declare that the direct interruption of the generative process already begun and, above all, all direct abortion, even for therapeutic reasons, are to be absolutely excluded as lawful means of regulating the number of children."
However, Catholic scholars with The National Catholic Review and AmericanCatholic.org make a distinction between "direct abortions" that is, abortion which is either an end or a means, and "indirect abortions." While the Church opposes all direct abortions, it does not condemn procedures which result, indirectly, in the loss of the unborn child as a "secondary effect." For example, if the mother is suffering an ectopic pregnancy, a doctor may remove the fallopian tube as therapeutic treatment to prevent the mother's death. The embryo or fetus will not survive long after this, but the intention of the procedure and its action is to preserve the mother's life, not to harm the embryo or fetus. Therefore, it is not a direct abortion.
While the positions in the previous two paragraphs appear in tension with one another, the relevant distinction may be between cases where the mother's life may be "in jeopardy," and cases where the mother would almost certainly die without the procedure that would—incidentally—destroy the fetus.
The Catholic Church also teaches that the inalienable right to life of every innocent human individual is a constitutive element of a civil society and its legislation. In other words, it is beholden upon society to legally protect the life of the unborn: "The moment a positive law deprives a category of human beings of the protection which civil legislation ought to accord them, the state is denying the equality of all before the law. When the state does not place its power at the service of the rights of each citizen, and in particular of the more vulnerable, the very foundations of a state based on law are undermined. . . . As a consequence of the respect and protection which must be ensured for the unborn child from the moment of conception, the law must provide appropriate penal sanctions for every deliberate violation of the child's rights."
According to a memorandum written by Cardinal Joseph Ratzinger, Catholic politicians who campaign and vote for permissive abortion laws should be warned by their priest to refrain from receiving communion or risk being denied the Eucharist until they change their political views. This position is based on Canon 915 and is also supported by Archbishop Raymond Leo Burke, Prefect of the Apostolic Signatura, the highest judicial authority in the Catholic Church besides the Pope himself.
Modern Catholic theologians trace Catholic thought on abortion to early Christian teachings such as the Didache, Barnabas and the Apocalypse of Peter. Some theologians trace pro-life Catholic advocacy to Saint Thomas Aquinas and Saint Augustine.
There are Catholic scholars who oppose the Church's position on abortion. Notably, philosopher Daniel Dombrowski wrote a "A brief, liberal, Catholic defense of abortion." In addition, Catholics for a Free Choice was founded in 1973 "to serve as a voice for Catholics" who believe individual women and men are not acting immorally when they choose to use birth control, and that women are not immoral for choosing to have an abortion. Catholics for a Free Choice believe:
Catholic support for legal abortion is grounded in core principles of Catholic theology, which respect the moral agency of all women. It is bolstered by respect for the religious freedom and rights of people of all faiths and no religious faith, by respect for plural and tolerant democratic societies and, most importantly, by adherence to the Catholic principle of standing with the poor and marginalized of the world who are disproportionately women.
The United States Conference of Catholic Bishops has made the statement that "[CFC] is not a Catholic organization, does not speak for the Catholic Church, and in fact promotes positions contrary to the teaching of the Church as articulated by the Holy See and the NCCB."
The Eastern Orthodox Church believes that life begins at conception, and that abortion (including the use of abortifacient drugs) is the taking of a human life. However, there are exceptions. The Basis of the Social Concept of the Russian Orthodox Church states that while abortion can never be seen as morally neutral, in some cases economy can be used:
In case of a direct threat to the life of a mother if her pregnancy continues, especially if she has other children, it is recommended to be lenient in the pastoral practice. The woman who interrupted pregnancy in this situation shall not be excluded from the Eucharistic communion with the Church provided that she has fulfilled the canon of Penance assigned by the priest who takes her confession.
The document also acknowledges that abortions often are a result of poverty and helplessness and that the Church and society should "work out effective measures to protect motherhood." All in all, while the Eastern Church lets the individual decide for herself whether or not they want to perform the action, it considers it a sin that requires confession and absolution and performance of a canon of Penance.
Protestant views on abortion vary considerably. Christian fundamentalist movements condemn abortion, while "Mainline Protestant" demonimations take more nuanced positions, but are generally pro-choice with some exceptions. Several mainstream Protestant organizations belong to the Religious Coalition for Reproductive Choice. These include the Episcopal Church, the Presbyterian Church (USA), The United Church of Christ, The United Methodist Church, the Unitarian Universalist Church, and the Lutheran Women's Caucus.
Despite their general opposition to abortion, fundamentalist churches that include the conservative evangelical, Non-denominational, Southern Baptist and Pentecostal movements, do not have a single definition or doctrine on abortion. While these movements hold in common that abortion (when there is no threat to the life of the woman) is a form of infanticide, there is no consensus as to whether exceptions should be allowed when the woman's life is in mortal danger, or when the pregnancy resulted from rape or incest. Some argue that the lives of both the mother and child should be given equal consideration, in effect condemning all abortion including those performed to save the life of the woman. Others argue for exceptions which favor the life of the woman, perhaps including pregnancies resulting from cases of rape or incest.
Before 1980, the Southern Baptist Convention advocated for abortion rights. During the 1971 and 1974 Southern Baptist Conventions, Southern Baptists were called upon "to work for legislation that will allow the possibility of abortion under such conditions as rape, incest, clear evidence of severe fetal deformity, and carefully ascertained evidence of the likelihood of damage to the emotional, mental, and physical health of the mother." W. Barry Garrett wrote in the Baptist Press, "Religious liberty, human equality and justice are advanced by the [Roe v. Wade] Supreme Court Decision."
Randall Herbert Balmer, Ph.D., argues in his book, Thy Kingdom Come, that despite the popular belief that anti-abortion sentiments galvanized the fundamentalist evangelical movement, what actually galvanized the movement was evangelical opposition to the American Internal Revenue Service (IRS). The IRS stripped evangelical universities, like Bob Jones University, from their tax-exempt status for remaining racially segregated.
Today, the Southern Baptist Convention, the largest Protestant denomination in the United States, opposes elective abortion except to save the life of the woman. The Southern Baptist Convention calls on Southern Baptists to work to change the laws in order to make abortion illegal in most cases. Richard Land, president of the Southern Baptist Convention’s Ethics and Religious Liberty Commission has said that making abortion illegal is more important than any other issue, including the fight against poverty.
The National Association of Evangelicals includes the Salvation Army, the Assemblies of God and the Church of God, and takes a pro-life stance. While there is no set doctrine among member churches on if or when abortion is appropriate in cases of rape or incest, or to save the life of the woman, the NAE's position on abortion states, "...abortion on demand for reasons of personal convenience, social adjustment or economic advantage is morally wrong, and [the NEA] expresses its firm opposition to any legislation designed to make abortion possible for these reasons."
The General Board of American Baptist Churches in the U.S.A. opposes abortion "as a means of avoiding responsibility for conception, as a primary means of birth control, and without regard for the far-reaching consequences of the act." There is no agreement on when personhood begins, whether there are situations that allow for abortion, whether there should be laws to protect the life of embryos and whether laws should allow women the right to choose an abortion.
Positions taken by Anglicans across the world are divergent although most would refrain from simplifying the debate into pro-choice or pro-life camps. The Church of England, for example, shares the opinion held by the Roman Catholic Church. In a 1980 statement, the church declared: "In the light of our conviction that the foetus has the right to live and develop as a member of the human family, we see abortion, the termination of that life by the act of man, as a great moral evil. We do not believe that the right to life, as a right pertaining to persons, admits of no exceptions whatever; but the right of the innocent to life admits surely of few exceptions indeed."
The Episcopal Church in the United States of America has taken a pro-choice stand and has passed resolutions at its triannual General Convention that supports woman's right to choose. The church opposes any government action that limits a woman's right to choose, including parental notification. The ECUSA does condemn abortions for sex selection and also condemns violence against abortion clinics.
The Anglican Church of Australia does not take a position on abortion. However, in December 2007, an all-woman committee representing the Melbourne diocese recommended that abortion be "decriminalised", on the basis of the ethical view that "the moral significance [of the embryo] increases with the age and development of the foetus". This is seen to be the first official approval of abortion by Australian Anglicans.
The Christian Church (Disciples of Christ) General Assembly has "repeatedly affirmed its support for the principles of a woman's right to reproductive freedom, of the freedom and responsibility of individual conscience, and of the sacredness of life of all persons. While advocating respect for differences of religious beliefs concerning abortion, Disciples have consistently opposed any attempts to legislate a specific religious opinion regarding abortion for all Americans." 
Lutheranism in the United States consists largely of three denominations: the Evangelical Lutheran Church in America (5 million members), the Lutheran Church—Missouri Synod (2.5 million members), and the Wisconsin Evangelical Lutheran Synod (0.5 million members).
The Evangelical Lutheran Church in America maintains a pro-choice position for fetuses that are aborted before viability outside of the womb. The ELCA position statement says abortion should be an option of last resort, the ELCA community should work to reduce the need for elective abortions, and that as a community, "the number of induced abortions is a source of deep concern to this church. We mourn the loss of life that God has created." The church opposes legal restrictions on abortion and provides health-care benefits to its employees that cover elective abortions. Some hospitals affiliated with the church perform elective abortions.
The two smaller United States denominations, which are considered evangelical, are pro-life. The Lutheran Church—Missouri Synod opposes abortion, except for cases when it is required to save the woman's life.
The United Methodist Church upholds the idea that church doctrine should not interfere with secular abortion laws. In light of grave or socio-economic circumstances, the United Methodist church believes in the right of the woman to choose whether to have an abortion, and is thus often regarded as pro-choice.
The Methodist Church of Great Britain has a nuanced pro-choice position. The Methodist Church of Great Britain believes its congregants should work toward the elimination of the need for abortion by advocating for social support for mothers. The MCGB does not believe abortion should be made illegal, and counsels that abortion should be done as early in pregnancy as possible.
The Presbyterian Church generally takes a pro-choice stance. The Presbyterian Church believes that the choice to receive an elective abortion can be "morally acceptable;" however, the Church does not condone late abortions where the fetus is viable and the woman's life is not in danger.
The Religious Society of Friends generally avoids taking a stance on controversial issues such as abortion; however, in the 1970s the American Friends Service Committee advocated for abortion rights.
The United Church of Christ has strongly supported abortion rights since 1971 as a part of their Justice and Witness Ministry. The church is an organizational member of the National Abortion and Reproductive Rights Action League (NARAL).
The Church of Jesus Christ of Latter-day Saints takes a position against abortion and holds that abortion is a form of killing. However, there are exceptions. According to a statement in the LDS library, "Some exceptional circumstances may justify an abortion, such as when pregnancy is the result of incest or rape, when the life or health of the mother is judged by competent medical authority to be in serious jeopardy, or when the fetus is known by competent medical authority to have severe defects that will not allow the baby to survive beyond birth." The statement goes on to say, "Those who face such circumstances should consider abortion only after consulting with their local Church leaders and receiving a confirmation through earnest prayer."
The Unitarian Universalist Church strongly supports abortion rights. In 1978, the Unitarian Universalist Church passed a resolution that declared, "...[the] right to choice on contraception and abortion are important aspects of the right of privacy, respect for human life and freedom of conscience of women and their families."
Pro-life under all circumstances:
Opposed, except in cases of danger to the woman's health:
Opposed, except in cases of rape, incest, or danger to the womans's health: