Dunno, lemme give it a shot:

First off, if a compromise can be found, that could solve the problem instantly - for example, if instead of abortion, a fetus could be removed and implanted safely in another woman, or in a laboratory, and brought to term, and there was a legal apparatus in place to ensure the child received care, that could eliminate the "killing" aspect of an abortion while preventing a woman from being forced to keep a rape-induced pregnancy to term.

That doesn't exist yet though, so, lemme try this, though I feel very dirty doing so:

If abortion is murder, then there's no legal justification in carrying it out because one is a victim of a crime, even if the abortion is a "solution" to one of the long-term effects of that crime (the rape). Just as one is not allowed to steal to replace stolen goods, one should not be allowed to "murder" an unborn child in response to a rape.

Well, you're not wrong, it's a pretty hard argument to make without bringing religion in.

If killing a person is murder, then there is no legal justification in carrying it out because one is a victim of a crime. Yet, in capital punishment cases, we go ahead and do so anyways.

There is also the religious assertion that in its present state, a zygote is a human being, yet, say, the biological matter that is removed from the body in a woman's period is not. I am not aware of an argument that does not hinge on the zygote being empowered by a magical soul.

Well, a zygote is a developing human being while a placenta is clearly not. You don't have to believe in a soul to think that all human beings -- regardless of their stage of development -- merit legal protection.

A pre-menopausal woman carries thousands of eggs. Are they all also not human beings? Does the average woman commit at least one murder a month? What about the nutrients that might be assembled into a human being?

Giving the 'undifferentiated mass of cells is clearly a human being' argument even a slight push very quickly devolves into absurdity.

They are not humans because they are not fertilized eggs. Unfertilized eggs are haploid, not diploid, meaning they are unpaired chromosomes (am ignoring X and Y). It also means they could not produce a living human... too many problems owing to the missing second chromosome in each pair. Is like having 25,000 gene deletions!

Some animals have a phenomenon called parthenogenesis which allows an unfertilized egg to develop into a living organism. This does not naturally happen in humans. (And I doubt it happens unnaturally.)

The biggest "murderer", using the definition of the religious people, is the "god" himself, as it is known that, biologically, many of the inseminated egg cells don't end up ever becoming babies, failing to attach to the uterus and getting ejected. Even many that attach don't survive long enough to develop, resulting in a natural "miscarriage" later. That's simply how the reproduction mechanisms work.

So why again should humans be punished when it happens all the time anyway "by design"?

> Well, a zygote is a developing human being while a placenta is clearly not.

In that case, pro-lifers should have no issues with a pregnant woman asking her doctor to remove her placenta - as long as they don't touch the zygote.

Wouldn't that equate to imprisoning someone but not providing them with food?

Or the equivalent of removing life support and having them die slowly and painfully, rather than simply administering an overdose of morphine. I do like that the issues blend at this point, though - removing the placenta is something I haven't considered. It would be legal because you can legally take someone off life support.

It seems to equate to imprisoning someone in the house of a very poor person who can only afford to feed themselves, and requiring that poor person to provide the prisoner with food, and then punishing the poor person when they refuse.

Do you prefer to force the mother to feed and host a parasitic child against her will? That's pretty uh...totalitarian.

Religion is the only place where you'll find people arguing that a zygote is a human, so I'll say it's impossible to make the argument without religion.

For a secular reference search "plead the belly".

That's a pretty bold claim that many disagree with.

Don't be shy: if it is so bold, why not explain why?

Feel free to present non-religious arguments that contradict the claim.

I'll bite.

Human life deserves protection. Human life starts at some point in time. Saying human life starts at birth (when the child leaves the womb), makes no sense. There is nothing unique about leaving the womb that infers humanity. There is nothing different between killing at newborn and killing a baby still in the womb who is past-due. Location doesn't infer something is a life or not.

So we need to find a better indication of when a human life begins. One could argue that if a child could live outside the womb, then it is a human life. Currently children commonly survive being born 26 weeks premature (3 months before being normally born). Again, killing a premature baby is no different than killing it in the womb. It's the same life.

Other believe that human life starts before that. Some believe that once the self-sustaining process of forming a baby starts (fertilization), then it's human life.

I'm not arguing for one or the other. However, I do understand why some people hold those beliefs.

The mother's life again gets zero consideration.

How about if we consider that she should not be forced to feed and carry a parasite against her will. It is risky, regularly including death and disfigurement. People love to talk about the right to life when they are referring to an innocent zygote but suddenly everything changes if the mother's rights are brought into it.

The argument is fairly straightforward if you accept -- as pro-lifers do -- that abortion constitutes the killing of an unborn child. Parents have a prima facie duty of care towards their children by virtue of the biological connection between parent and child, and this duty of care exists regardless of the circumstances of the child's conception.

This position in no way denies that rape is gravely immoral. It simply recognizes that the child is not responsible for the crimes of his father. The injustice of rape does not justify the additional injustice of abandoning or killing one's own child.

I think most people have no difficulty accepting this argument at least with respect to born children. Nobody would argue that infanticide, for example, is an appropriate response to rape. But there's no reason why the same logic doesn't apply before birth as well.

> It simply recognizes that the child is not responsible for the crimes of his father. The injustice of rape does not justify the additional injustice of abandoning or killing one's own child.

Yet the implicit argument here is that the injustice of rape DOES justify the additional injustice of forced pregnancy upon the victim. Pregnancy involves a profound set of changes to the body, not all of them temporary. I find it incredibly unjust that people are willing to argue that the rights of a handful of cells that will eventually become a human outweigh the rights of an inarguably human woman whose body was forcibly violated, by way of causing a second, 9-months-long forced violation of her right to control her own body. A concrete reminder of the rape that she cannot ignore because it's literally inside her and growing every day. It's despicable.

This is not to mention the lesser injustice of failing to provide her with any assistance during the pregnancy--she will need to consume more calories, will eventually find it difficult or impossible to perform her work duties until the child is born, etc. Where is that assistance provided for in all this legislation?

And for that matter, where are the appeals to the duty of caring for one's children when an adult with young kids is carted off to prison? Clearly there are circumstances in which that duty is superceded by some set of societal concerns. Why is conception by rape not one of them while some crime committed by a parent is?

A typical answer to this is to develop notions of a "moral community" and individuals that belong to it[1]. Those within the moral community can make certain basic claims, thus rights, on others within it such as a right to life. Depending on how you define membership within the moral community, you can make an argument that (early stage) abortion is permissible but infanticide is not.

[1]: http://www.csus.edu/indiv/g/gaskilld/ethics/abortion.htm

I rarely bring up nazis but this sounds like something that could have been fetched straight out of nazi Germany:

they had a number of programs for getting rid of unwanted individuals and actually not only forced people but also did public (IIRC) outreach to sell the idea to doctors and parents of severly disabled or otherwise unwanted kids.

(Long time since last I read about this but I think "aktion t4" and "Tiergartenstraße" is the thing to search for if anyone is interested.)