"I would say that as an ardent, practicing Catholic, this is an issue that I have studied for a long time. And what I know is, over the centuries, the doctors of the church have not been able to make that definition. And Senator–St. Augustine said at three months. We don’t know. The point is, is that it shouldn’t have an impact on the woman’s right to choose. Roe v. Wade talks about very clear definitions of when the child–first trimester, certain considerations; second trimester; not so third trimester. There’s very clear distinctions. This isn’t about abortion on demand, it’s about a careful, careful consideration of all factors and–to–that a woman has to make with her doctor and her god. And so I don’t think anybody can tell you when life begins, human life begins. As I say, the Catholic Church for centuries has been discussing this, and there are those who’ve decided…"
The Catholic Church teaches life begins at conception. It has been since at least 70 CE.
"From its conception, the child has the right to life. Direct abortion, that is, abortion willed as an end or as a means, is a “criminal” practice (GS 27 § 3), gravely contrary to the moral law. The Church imposes the canonical penalty of excommunication for this crime against human life."
From the debate: