Kenneth Glad
A scientific review published earlier this month has poured cold water on one of space exploration’s longest-running assumptions. The paper argues that human reproduction beyond Earth remains far out of reach.
The timing is deliberate. As governments and private companies move from test flights to talk of permanent settlements, the authors say that biology is being asked to keep pace with engineering. It isn’t though.
The paper was released in the journal Reproductive BioMedicine Online. It is a narrative review that draws on several decades of research across space medicine, reproductive biology and developmental science. Written by more than a dozen authors from academic and clinical institutions, it examines dozens of prior studies rather than presenting new experimental data.
A cautious consensus
Their shared position is clear, according to The Mirror: Pregnancy and childbirth in space should not be attempted at this stage. Instead, the authors argue that protecting fertility and understanding risk must come first, before settlement plans become fixed.
Lead author Giles Palmer, a clinical embryologist and executive director of the International IVF Initiative, said the goal is to prepare for foreseeable risks as mission durations increase, not to encourage reproduction in orbit.
Rather than isolating single threats, the review focuses on how harms could build over time. Radiation exposure may introduce genetic damage that accumulates across generations. Altered gravity could interfere with development in ways that are subtle, delayed and difficult to reverse.
“Space radiation can damage DNA, disrupt gamete formation, and raise cancer risk, while microgravity interferes with hormonal regulation, gamete quality, and embryonic development,” Palmer said.
The authors also point to less dramatic, but persistent, pressures: Disrupted sleep cycles, chronic stress, contamination risks and limited medical intervention. Taken together, they argue, these conditions could undermine not just individual pregnancies, but the long-term health of any off-world population.
Limited human evidence
Human flight data remains thin. Existing evidence comes largely from relatively brief missions, which offer only a partial picture of long-term reproductive effects. Beyond that, the record is patchy.
Animal studies suggest cause for concern, but researchers disagree over how directly those findings apply to humans. Some believe future shielding and medical countermeasures will solve much of the problem. Others are less convinced.
The review does not try to settle that argument. It highlights it.
Instead of experimentation, the authors argue for an international framework governing reproductive research in space, with strict ethical oversight and clear limits.
They conclude that advances in assisted reproductive technologies may eventually reduce some risks, but only if paired with transparency, informed consent and protection of future offspring.
This debate has echoes of earlier moments in medicine, when technological confidence ran ahead of evidence. With geopolitical rivalry and commercial pressure now shaping spaceflight, the authors suggest restraint may be the safer option.
The bottom line is simpler than the rhetoric around space settlement. We can send people farther than ever. Making new people out there is another matter.
Sources: Reproductive BioMedicine Online, The Mirror
