However, the canon laws of the church on abortion remained unchanged for a long time until Pope Pius IX dropped the distinction between the "fetus animatus" and "fetus inanimatus" in 1869 -- ending the tolerant approach of the church towards abortion, which continues to this day.
The current Christian belief about abortion is largely based on the anti-abortion references in the scriptures in which life was considered to be a sacred gift from God, the womb being an inviolable place and the idea that life starts at the time of conception. At the same time, the Christian anti-abortion groups have also included some popularized scientific beliefs about pregnancies and abortion in their arsenal to counter the "pro-choice" and feminist arguments in favor of abortion.
For example, the "freedom of choice" pro-abortion argument that a woman has a right of control over her own body and, therefore, should have the right to terminate unwanted pregnancies is countered by the contention that an unborn child is a distinctly separate individual and no one has the right or 'freedom' to end the life of another individual. Hence, restriction on abortion is by no means a violation of 'fundamental rights' of a woman as such 'freedom of choice' does not apply to terminating the life of another individual, i.e., the unborn fetus. The Christian churches and religious pro-life groups now also frequently quote scientific evidence that an unborn fetus has a beating heart, tiny little fingers and toes by just 18 days after fertilization and is not just "a blob of tissue" to be callously discarded.
Another 'feminist' argument about abortion rights, i.e., that the women should have the right to abortion so that they are not disadvantaged viz a viz the men in the job market is also bitterly opposed by the Christian groups. They believe that women's main purpose in life is to participate in "the miracle of life" and the perception in our society about the incompatibility of successful working women with pregnancy is termed by them as a "fallout of our society's failed value system." (Terwilliger, para on "Abortion.")
The opposition to abortion among the Christians is, as should be expected, not absolutely consistent; it is strongest in evangelical, fundamentalist, or pentecostal churches (e.g. Baptists, Assemblies of God), as opposed to the 'mainline' liberal churches such as Methodist, Presbyterian, and Epicospalian. Some of the evangelical churches, for instance, take the extreme position that abortion is not permissible even in cases of rape and incest, arguing that one sin (rape) does not justify another sin (abortion). On the other hand, most mainline churches and ministers favor legal abortions in instances of rape, incest, or when the health of the mother is jeopardized. None, however, support abortion on demand as is the position of the pro-choice groups. (Jelen, 134-142)
The Christian beliefs about abortion have completed a full circle since the biblical times. Initially, the Christian church was firmly opposed to all forms of abortion and considered it a dire sin. In the middle period, the Church changed tracks and allowed abortions in early pregnancy. Since the 17th century, Christians have reverted back to their original stance on abortion with the fundamentalists and evangelists being more strident in their opposition.
Jelen, Ted G. "The Clergy and Abortion." Review of Religious Research. 34.2 (1992): 132-151
"Presbyterians and Abortion: Historical Christian Perspectives." Presbyterians Pro-Life. N.d. January 4, 2005. http://www.ppl.org/hist_xn.html
Robinson, B.A. "Abortion: Ancient Christian Beliefs." Religious Tolerence.org. March 07, 2004. January 4, 2005. http://www.religioustolerance.org/abo_hist.htm
Terwilliger, M. "Sex, Abortion, Birth Control, and Christianity." June 12, 2003. January 4, 2005. http://www.epigee.org/guide/foreword.html
According to the Christian belief of the time, an 'animated' fetus was the one in which a human soul had entered -- 40-80 days after the conception or when the woman first felt the movement of the fetus
"Fetus animatus": animated fetus; "Fetus inanimatus": fetus of early pregnancy -- before the soul was supposed to have entered it.