I know abortion is wrong, but how can I tell others why it is wrong? A troubled teen.

There are two approaches you can take. The first is to try to persuade people using moral principles which we all generally accept. The second is to appeal to revelation, i.e., the God’s teaching.

Begin with the idea that no one has the right to take the life of an innocent person.

Then discuss how the baby is a separate human being. The mother is not the baby, nor the baby is the mother. They are two separate human beings.
Show how each child has its unique genetic identity. For instance, it has its own gender (if it’s a boy), its own heart beat, brain waves, blood-type, eyes, hands, feet and so on.

Challenge them to consider whether society is going backwards, not forward, when it permits babies to be killed by abortion to solve its problems.

Acknowledge that women do have certain rights over their bodies just as men do, but these rights are limited when they involve other people’s bodies.

Abortion directly involves at least two bodies, the mother’s and her unborn child’s, not to mention the father’s.

Then discuss God. Mention the Bible teaches children are a gift from God and that God knows and loves each child from his or her first moment in the womb (Jer. 1:5; Is 41:2, 44:24).

Then ask, “Do you think God is pleased that His precious gifts are being brutally killed in the supposed safest place on earth – the mother’s womb?”

Also ask, “Supposed you were that baby who is about to be aborted, how would you feel?”

If people tell you not to bring religion into it, take your stand as a Catholic. Tell them that EVERYTHING is ultimately a religious issue. God’s law exists. You didn’t make it up. You are just telling them what God wants and what His law is.