So many pregnancies end in miscarriages, especially very early ones. Does the Church view miscarriages as actual deaths?

We have not traditionally had funerals and coffins for spontaneous miscarriages. Does that mean we didn't say they were persons? No. But we kind of let that one fall between the cracks. If parents wish to remember them, they're welcome to remember them. If they want to give them a name, that's all right. Rick Santorum did that. But in the case of Emily Herx, what you see is the conservative side of the Church trying to tighten boundaries that were sometimes left a little bit vague.

Emily Herx told her school that she wasn't going to destroy any embryos during her IVF treatment. So why was there a problem?

There's still an issue. In terms of procreation, the closer one is to sexual intercourse, the less the Church is going to have a problem with it. So if you're doing fertility treatments that help you conceive while actually having sex, that's mostly all right. The further you move from that -- and toward the laboratory actually playing a role in conception -- the less the Church approves.

And then there's the issue of using borrowed sperm or ova, which adds another layer of distance. The further things move away from sexual intercourse, the more it raises the question: Are you manufacturing a baby? Is this an extension of lovemaking? Or is the laboratory doing something to replace lovemaking?

The whole idea of conceiving a baby outside the womb is so modern. It's hard to imagine these issues coming up in any form in the early Church.

Yes. But when it comes to sexual things, the Catholic Church has always held that the sperm belongs with the ovum, the male genital part belongs in the vagina. From that, you can deduce almost anything.

A lot of babies are conceived in circumstances that don't seem particularly holy -- a one-night stand, or even a rape. In contrast, two people undergoing fertility treatments would seem to be especially committed to each other and to their future family.

Precisely. Sometimes Catholic theologians can be very insensitive about that. They'll talk to a couple who have loved each other, have gone through pain together, and might be struggling with issues about their masculinity or femininity, and they'll say, "Moral theology says you don't have the right to have a child." That might be correct on a blackboard. But to say that to a couple is like telling them what selfish, evil people they are. They're loving people who want a child badly -- and they know the Church wants people to have children, so they can't understand why they aren't getting more empathy.

But the Church does disapprove of in vitro fertilization, no matter how loving and committed a couple may be.

When it comes to sexuality, our Catholic natural law teaching is very genital-based. It's more focused on biology than Catholic teaching is in other areas. Some would say that love, marriage, and commitment have to be taken into account. Pope John Paul II worked very hard to create what he called the theology of the body -- instead of just talking about biology, he spoke about the loving meaning of the whole person. But in the end, the Church would say that you can't go against biology. That's the mechanics of our nature.