A pro-choice friend of a friend offered the following challenge to pro-lifers:

There is a legal concept called bodily autonomy. Legally, you can’t compel another person to provide you with life support at the expense of that other person’s authority over their own body. You can’t make them so much as donate blood. Even if that person’s blood will completely guarantee your own survival in the face of what would otherwise be certain death, and not affect their own survival in the slightest.

How much more invasive is it to be compelled to provide a complete life support system for something that for many months has more in common with an elephant fetus than with an adult human?

How to respond to this?

To start with, if you have the power to save another’s life by donating blood — if “that person’s blood will completely guarantee your own survival in the face of what would otherwise be certain death, and not affect their own survival in the slightest” — and you refuse to do so, then the law may not be able to compel you to do so, but to refuse would be gravely morally wrong.

Let’s begin there.

Donating blood is praiseworthy, but under normal circumstances it isn’t gravely incumbent upon any particular person to donate blood at any particular time, since normally no particular person is uniquely dependent on any other particular person to give blood.

Yet in some situation in which a particular person’s life did depend entirely on your action or inaction, and you refused to act, whatever our system of law can or can’t oblige you to do, you would become morally culpable for that person’s death.

This is the case, note, even though refusing to save someone’s life involves a choice not to act rather than a positive, violent action to end their life. Inaction leading to someone’s death can be gravely wrong, but direct violent action against the life of an innocent human being is worse — and here the law can compel.

We can’t legally require people always to do the right thing — but we can certainly legally require people to refrain from taking direct, violent action against the lives of innocent human beings.

On the other hand, the pro-choice argument rightly points out that giving blood is a trivial obligation compared to carrying a child to term.

The demands of pregnancy are immense and intimate in a way that defies analogy. For about nine months the mother’s body seems to be, in a practical sense, not entirely her own; she shares it, every minute of every day, with someone else.

Arguments around the humanity of the child, and appeals to historical precedents where some human beings were denied their full human rights (e.g., Nazi Germany; antebellum slave states), can gloss over what is unique about the abortion debate.

To acknowledge the full humanity of slaves or Jewish people, to respect their right to life, imposes only an obligation to treat them like anyone else: to release them from chains and camps, to reject the horrors of the slave market and the Final Solution.

To acknowledge the full humanity of unborn children, to respect their right to life, imposes a very different obligation — one that falls solely on the mother — going far beyond the ordinary demands of recognizing human dignity and the right to life.

Yes. That’s because the obligations of parents to their children, their own flesh and blood, go far beyond the ordinary obligations of humans toward one another.

One’s own child is not a stranger or outsider to whom one has only the ordinary obligations. If the children next door are hungry, depending on circumstances you might or might not have some moral obligation to them — but if your own children are hungry, your obligation is far more profound. And while the law will not compel you to feed the children next door, it will certainly compel you to feed and provide for your own.

We can’t gloss over the unique demands of pregnancy (demands regarding which each of us is dependent for our whole existence on the woman who gave birth to us). But, by the same token, we can’t gloss over the simple and obvious fact of the unborn child’s humanity either.

When an elephant cow conceives, the life in her is an elephant from conception onward. It is never any species but elephant; it is never a fish, a reptile or a bird.

When a woman conceives, the life in her is always a member of the human family. A human zygote, embryo or fetus never a dolphin, a monkey, or an elephant. It is one of us, a sharer in our common human nature, possessing human dignity from the start.

The ultimate basis for a mother’s obligation to her child is simply her child’s utter dependence on her: a dependence that is an essential part of human nature, a state in and through which we all come into the world. The child is not an invader or alien in the mother’s body. He or she is flesh of her flesh.

Human beings are not autonomous islands. We do not encounter each other only like sovereign countries, entering into diplomatic relations and taking on responsibilities to one another only when and where we freely choose to do so. Our lives, relationships and responsibilities are shaped by many factors over which we have little or no control.

None of us chose to come into existence in a state of total dependence. None of us chose the parents to whom we find ourselves indebted with special obligations of obedience and honor. Those with siblings did not choose to share their lives and parents’ energies and attention with them; those without siblings did not choose to be only children.

Human beings are differentiated and divided by many things: race, ethnicity and skin color; sex and sexuality; nationality, language, culture and religion; legal, social and economic status; age and stage of development; etc.

Yet we are all members of one family, one human race, with a common human nature and a shared human dignity that is universal to all. My claim to my worth or value as a human being is inseparable from my obligation to recognize that your life and your dignity are worth no less than my own, regardless what differences may be between us. We cannot deny or diminish one another without denying and diminishing ourselves.

The obligations of human dignity go beyond religious or ideological allegiances. The recognition that your life and your dignity are worth no less than my own is not an obligation only for members of a particular religious or ideological tradition; it is an obligation of our very humanity.

Human dignity is the foundation of human rights. All members of the human family are entitled to the recognition of their human rights, starting with the right to life.

Human rights deserve the protection of law. The protection of law is especially urgent in the case of those who are in any way weaker, less advantaged or less able to defend and protect themselves.

A system of law that doesn’t hold sacred the lives of every member of the community is unjust and inhuman.