All persons, not just Catholics, can know from the scientific and medical evidence that what grows in a mother's womb is a new, distinct human being. All persons can understand that each human being -- without discrimination -- merits respect. At the very least, respecting human life excludes the deliberate and direct destruction of life -- and that is exactly what abortion is.
Catholics are also pro-life because our Christian tradition is pro-life. As Pope John Paul II says, Christians believe that "all human life is sacred, for it is created in the image and likeness of God." Aborting an unborn child destroys a unique creation which God has called specially into existence.
Christian teaching also obliges us to follow in the footsteps of Jesus Christ, who spoke and acted strongly and compassionately in favor of the most despised and vulnerable persons in society. Jesus touched lepers, spoke with prostitutes, and showed special mercy and tenderness to the sick, the poor, and children. Our society today has many vulnerable persons --- including women in crisis pregnancies as well as unborn children whose lives may be legally ended at any time during pregnancy and for any reason. In the tradition of Jesus Christ, Catholics have a responsibility to speak and act in defense of these persons. This is part of our "preferential option" for the poor and powerless.
The Church's mission to defend human life applies over the entire course of life, from conception to natural death. And so the Catholic Church has been a strong supporter of the civil rights movement and a leader in international relief and development efforts. Catholic hospitals and other health-care facilities form the largest network of private, not-for-profit health care providers in the United States. Catholic Charities USA --- one of a number of Catholic charitable groups --- is currently the single largest provider of social services to all Americans, regardless of race, creed or national origin.
The Catholic Church strives to be a prophetic voice, speaking out to protest injustices and indignities against the human person. Catholics will continue in this work, whether our words are popular or unpopular.
Since its beginnings, Christianity has maintained a firm and clear teaching on the sacredness of human life. Jesus Christ emphasized this in his teaching and ministry. Abortion was rejected in the earliest known Christian manual of discipline, the Didache.
Early Church fathers likewise condemned abortion as the killing of innocent human life. A third century Father of the Church, Tertullian, called it "accelerated homicide." Early Church councils considered it one of the most serious crimes. Even during periods when Aristotle's theory of "delayed ensoulment" led Church law to assign different penalties to earlier and later abortions, abortion at any stage was still considered a grave evil.
When biologists in the 19th century learned more about the process of conception, the Church altered its legal distinction between early and late abortions out of respect for reason and biology.
Since that time, science has only further confirmed the humanity of the child growing in the womb. Official Church teaching insists, to the present day, that a just society protects life before as well as after birth.
The reasons are not difficult to understand. One official Church document on the subject puts it this way:
"The first right of the human person is his life . . . It does not belong to society, nor does it belong to public authority in any form to recognize this right for some and not for others; all discrimination is evil. . . Any discrimination based on the various stages of life is no more justified any other discrimination. . . . In reality, respect for human life is called for from the time that the process of generation begins. From the time that the ovum is fertilized, a life is begun which is neither that of the father nor of the mother; it is rather the life of a new human being with his own growth."
Declaration on Procured Abortion, Congregation for the Doctrine of the Faith (1974), paragraphs 11-12.