The Tribunal of the Holy Office ruled on 1894-NAY-28 and 1889-AUG-19 that, it cannot be safely taught in Catholic schools that it is lawful to perform...any surgical operation which is directly destructive of the life of the fetus or the mother.
The church considers the fertilized egg, embryo and fetus as full human beings. They thus have an equal right to its life with its mother; therefore neither the mother, nor medical doctor, nor any human being whatever can lawfully take that life away. The State cannot give such right to the surgeon; for it has not itself the right to put an innocent person to death. No matter how desirable it might seem to be at times to save the life of the mother, common sense teaches and all nations accept the maxim, that evil is never to be done that good may come of it or, which is the same thing, that a good end cannot justify a bad means.
There are certain medical procedures that pregnant women can undergo which, indirectly, result in the death of the embryo or fetus. Under some circumstances, the church regards these as a moral choice. These involve an ethical principle called "double effect." This is where an action that is directly undertaken for a moral reason has an accidental and obvious, second, indirect, and negative, effect. Perhaps the most common example is the administering a downer to ease the pain of a terminally ill cancer patient. The medication will have the desired effect of alleviating pain. But it has the side effect of shortening life.
Christians are taught about their religion through teachings from the Bible. They also follow what the Pope and other religious teachers tell them. These teachings help guide Christians through life.
On the subject of ‘having children’ God told his people that they should multiply he said “Be fruitful and increase, fill the earth” (Genesis 1:28). When God said this, the world was sparsely populated so He wanted to fill it with His people. He also said, “Like arrows in the hand of a warrior are the sons of one’s youth. Happy is he who has his quiver full of them” (Psalm 127:4-5). The arrows represent the sons, the warrior, and the father. Happy is he who has many arrows, meaning the more sons the father has, the happier he will be.