The following essay is being published in conjunction with the “(In)hospitable Space Conference” which explores the human dimensions of space exploration and is cosponsored between the English Department of Carnegie Mellon University, the Society for Social and Conceptual Issues in Astrobiology, and the European Astrobiology Institute.
A child born on Mars would not simply be a child born somewhere else. It would be born inside a machine. That machine could be beautiful. It could contain gardens, schools, clinics, laboratories, and windows overlooking the red horizon. It could be safer than the first ships that carried people across the oceans. It could be the result of extraordinary courage and intelligence. Nevertheless, it would be a machine and nothing more than a machine: a closed technological system on which every breath, meal, medical treatment, lesson, and social opportunity would depend. Even in the boldest and most daring visions of futurists, we will likely never be able to replicate what the natural environment provides us for free. Therefore, the ethics of space settlement cannot end with the question of whether we can make space habitable. We must also ask whether a habitable space should become a reproductive space.
Outer space is often described as hostile, and for good reasons. It lacks breathable air, stable temperatures, familiar gravity, and the usual safeguards that Earth provides us every second of our lives. To live beyond Earth, humans would need recycling systems, radiation shields, medical infrastructure, and many other life-support systems. A space colony would be a world created by engineers, administrators, doctors, and mission planners. Making space habitable usually sounds like an obvious ethical good. If we can build safer stations, more humane shelters, and eventually settlements on the Moon or Mars, why would we not? More habitability seems to mean more life, more possibility, more future. Yet this assumption hides a deeper problem. Making space livable for existing people is one thing. Creating new people there is another.
Adult astronauts and settlers can, at least in principle, accept danger for science, refuge, exploration, or adventure. A child born in a space settlement cannot consent to the world into which they are born. They would arrive inside a controlled atmosphere, a rationed economy, a small political community, a medical experiment, and perhaps a place from which ordinary exit is impossible.
Much of the moral imagination surrounding space settlement is still governed by the ark. Humanity is fragile. Earth is vulnerable. Extinction would be catastrophic. Therefore, we must build another vessel for life. And an ark, by definition, is supposed to carry life forward. It does not merely rescue the living; it preserves the species through reproduction. But should every ark have children?
The argument for space settlement often begins with survival. If humanity remains on one planet, a single disaster could end us. Nuclear war, engineered pandemics, ecological collapse, asteroid impacts, or other existential risks might make Earth uninhabitable. Philosophers such as Nick Bostrom and Toby Ord have made existential risk a central moral concern: if humanity has a future, then protecting that future matters. Their concern is serious. Human extinction would mean not only the deaths of existing people, but also the disappearance of cultures, languages, projects, and possibilities.
Yet preventing extinction and creating off-world reproductive populations are not the same claim. Preventing the death of existing persons belongs to an ethics of rescue. Creating future persons belongs to an ethics of procreation. The first asks how to protect those who are already vulnerable. The second asks whether we may create new vulnerable beings for the sake of a larger project. Space makes this second question harder, not easier.
On Earth, children are also born into worlds they did not choose. They inherit laws, languages, families, and ecological conditions shaped by others. But terrestrial societies are usually open in ways that space habitats would not be. A person may leave a town, encounter different institutions, join another community, disappear, or at least imagine exit. In a lunar base, a Mars settlement, or a generation ship, those options may be radically constrained. Air, food, water, education, work, and social life could all depend on the same structure. To create a child under those conditions is to place a person inside an institutional experiment.
This is why the ethics of procreation matters. David Benatar has famously argued that coming into existence is always a harm. One need not accept that strong conclusion to see the force of the challenge. Seana Shiffrin’s argument is especially relevant: creating a person imposes serious unconsented risks and harms for the sake of benefits that do not rescue a pre-existing person from deprivation . Rivka Weinberg similarly describes procreation not simply as a gift, but as the imposition of a lifetime of risk.
A child born in space might later love life, and their life might be meaningful. That matters, obviously. Antinatalism becomes morally crude if it treats all positive self-understanding as illusion. Still, a person’s later affirmation of life does not automatically prove that others were justified in creating that life under the conditions in question. A life can be worth living and still have been wrongfully imposed.
Space reproduction also remains scientifically uncertain. Researchers are only beginning to examine what conception, pregnancy, fetal development, and childbirth might mean under altered gravity, radiation exposure, confinement, psychological stress, and dependence on artificial life-support systems. These are often described as technical problems to be solved. But when uncertainty is imposed on a future child, it is not merely a planning risk – it becomes part of someone’s body and someone’s life.
This is why space settlement should begin from a restrictive presumption that no reproduction in space is allowed unless the habitat can meet demanding conditions of safety, medical care, education, privacy, dissent, and long-term autonomy. However, this is not a call for coercive antinatalism or hostility to families. It is a recognition that the burden of justification is much heavier in a closed world.
The temptation to treat future children instrumentally will be unusually strong in space. Small settlements need workers and caregivers. Political leaders may want symbols of permanence. The first child born on Mars would be more than a child in the public imagination. They would be evidence that a mission had become a civilization.
That symbolism is dangerous. No child should be created as a worker, caregiver, genetic resource, demographic stabilizer, or emblem of human destiny. Of course, children may grow up to care for others, build institutions, and continue communities. But those later possibilities cannot justify creating them in advance for the needs of the settlement. According to Kant’s ethical ideal, no human being may be treated merely as a means to an end. It is unclear whether people destined to live in a space colony would be treated merely as means to an end.
This is especially important when we think about care. Some philosophers have argued that procreation might, in certain circumstances, help solve the problem of an aging population: if a last generation will suffer because there are no younger caregivers, perhaps creating another generation can look like an act of aid. The thought is understandable, it begins from compassion for the dependent. But it quickly turns care failure into birth policy. Instead of asking how institutions should value care, distribute labor, support disability, and accompany aging, the burden shifts toward reproduction.
In space, this logic could become brutal. The elderly person needs care. The pregnant person becomes a reproductive asset. The child becomes future labor. The caregiver becomes infrastructure. Everyone becomes valuable because everyone is useful. A habitat organized this way may survive biologically while failing morally. This is where we need a different image: not the ark, but the hospice.
A hospice habitat is a care habitat. It does not celebrate extinction, suffering, or decline. Rather, it refuses to treat continuation as the only measure of success. A hospice is built around dignity under conditions of finitude. It asks how people can live well when cure, escape, or indefinite survival may no longer be available.
Applied to space, a habitat may be ethically successful even if it does not reproduce. It may support research, art, education, friendship, exploration, and care for those already alive. It may be not only temporary and finite, but it may also even be a last human community. Its success should not be measured by whether it creates descendants, but by whether it protects dignity, reduces suffering, preserves autonomy.
Human beings often draw meaning from the thought that life will continue after them. Samuel Scheffler has argued that many of our projects depend on confidence in a collective afterlife: the expectation that other humans will live on after we die. This helps explain why extinction feels not only frightening but meaning-destroying. Why write books, build schools, protect ecosystems, or pursue justice if there is no one after us?
But our need for future-oriented meaning does not give us a right to create future people. We may preserve things we find valuable, without demanding descendants. Harry Frankfurt and Susan Wolf, responding to Scheffler, suggest that value can remain even under doomsday conditions. Friendship, relief of suffering, solidarity, and love do not become worthless simply because they are finite.
A hospice habitat would take that seriously. It would preserve meaning without turning reproduction into an obligation. It would also make exit ethics central. Exit ethics concerns the moral limits of other people’s claims on one’s continued existence. In space, ordinary exit may be impossible. A person cannot simply leave the settlement and walk away from the mission. That makes autonomy more fragile. Consent given before launch cannot authorize every future burden. Because people change, they are not always able to continue the role assigned to them.
A humane habitat must therefore ask not only how to keep people alive, but how to respond when a person refuses treatment, declines further mission duties, rejects reproductive expectations, or finds life unbearable.
A minimally decent space habitat would need palliative care, mental health care, explicit refusal rights, advance directives, and safeguards against resource-driven decisions. No one should feel that they must keep living because the mission needs them. No one should feel that they should die because oxygen, medicine, or labor are scarce. No one should be kept alive, medically treated, or reproductively available simply because the settlement has goals. This is the right not to be kept for the mission.
The language of making space amenable can mislead us because it suggests that every ethical problem is solved by better design. Better design matters. But some moral defects cannot be solved by comfort. A beautiful habitat may still be coercive, and a caring community may still impose life for reasons of survival. Making space livable for existing people is a duty of care. Making space reproductive is a burden-imposing act.
It is worth noting that the antinatalists’ contribution to space ethics does not stem from a hatred of life. Rather, it is a demand for justification in a context where technological optimism, often implemented within a nationalist-military framework, frequently offers nothing more than symbolism tinged with colonialism. Antinatalist bioethics reminds us, however, that before we celebrate the birth of the first child beyond Earth, we should ask into what reality it has been born, what alternatives it will have, and whether it is accepted as a person or drawn into a civilizational project. Not every ark needs children. Some survival projects should be designed first and foremost for those who are currently alive, to care for them well, and to accept the fact that ending without abandonment is not synonymous with failure.
