Reproduction in space, an environment hostile to human biology

(Press-News.org) As commercial spaceflight draws ever closer and time spent in space continues to extend, the question of reproductive health beyond the bounds of planet Earth is no longer theoretical but now ‘urgently practical,’ according to a new study.

‘More than 50 years ago,’ explains clinical embryologist Giles Palmer from the International IVF Initiative Inc, ‘two scientific breakthroughs reshaped what was thought biologically and physically possible - the first Moon landing and the first proof of human fertilisation in vitro. Now, more than half a century later, we argue in this report that these once-separate revolutions are colliding in a practical and underexplored reality: space is becoming a workplace and a destination, while assisted reproductive technologies have become highly advanced, increasingly automated and widely accessible.’

But despite these advances, there are still no widely accepted, industry-wide standards for managing reproductive health risks in space, including the risks of inadvertent early pregnancy during space travel, fertility impacts from radiation and microgravity, and the ethical boundaries around any future reproduction-related research. The report, produced by an international expert group, aims not to promote conception in space but to highlight foreseeable reproductive risks for space travellers and to identify the scientific and ethical gaps that must be closed before irreversible harm occurs.

The nine authors of the study, published in the peer-reviewed journal Reproductive Biomedicine Online, include experts in reproductive health, aerospace medicine and bioethics, and they propose a collaborative framework to guide the next generation of reproductive research in space.(1)

What is known so far from limited laboratory and human studies from previous missions is that space, ‘an increasingly routine workplace’ today, is ‘a hostile environment’ for human biology to thrive. This is manifest in several conditions known to be detrimental to healthy reproductive processes, notably altered gravity, cosmic radiation and circadian disruption.

For example, while studies in animal models have shown that short-term radiation exposure adversely disrupts female menstrual cycles and increases the risk of cancers, this review found limited reliable data from male or female astronauts following longer missions in space. The effect of cumulative radiation exposure on male fertility remains a ‘critical knowledge gap’.

What makes the need for evidence more crucial is the greater time now spent by a greater number of people in space. Data recorded so far from female astronauts from the Shuttle missions reassuringly indicate that subsequent pregnancy rates and complications are comparable to those of age-matched women on Earth, but little has so far been reported from longer-duration missions in both men and women. This, write the authors, will require new evidence ‘to guide diagnostic, preventive, and therapeutic strategies in extraterrestrial environments’.

Can developments in today’s reproductive medicine help? While pregnancy remains a contraindication to space flight, and menstruation is usually avoided through hormonal methods, some technologies in automated laboratory techniques for fertilisation and cryopreservation may ‘align with the operational demands of space-based reproductive research and practice’.

‘Developments in assisted reproductive technologies often arise from extreme or marginal conditions but quickly extend beyond them,’ says Giles Palmer. ART is highly transferable because it addresses situations where reproduction is biologically possible yet structurally constrained by environment, health, timing, or social circumstance, constraints that already exist widely on earth.’

Although the scenario of human reproduction in space presently belongs more to science fiction than reality, the prospect does, however, demand ethical consideration - from the basic disclosure of pregnancy in space travellers or their genetic screening. It further seems likely that space research will extend further into reproductive biology, and that too may raise ethical questions. Clear policies are slowly emerging, but there are still no widely accepted guidelines on these subjects. Nor is enough known about the risks of pregnancy in long-duration space flights. What protections are in place? Who would bear responsibility? Would male fertility be compromised?

IVF technologies in space are no longer purely speculative,’ says Palmer. ‘It is a foreseeable extension of technologies that already exist. Gamete preservation, embryo culture and genetic screening are mature, portable and increasingly automated. As human activity shifts from short missions to sustained presence beyond earth, reproduction moves from abstract possibility to practical concern.’

The report thus argues that action is needed now, not because ART in space is imminent, but because the window for setting boundaries is closing. Treating these concerns as speculative misunderstands how reproductive technologies enter practice: incrementally, quietly and often justified after the fact. In this context, urgency means responsibility in advance - because governance delayed is governance denied.

‘As human presence in space expands, reproductive health can no longer remain a policy blind spot,’ says Dr Fathi Karouia, senior author of the study and a research scientist at NASA. ‘International collaboration is urgently needed to close critical knowledge gaps and establish ethical guidelines that protect both professional and private astronauts - and ultimately safeguard humanity as we move toward a sustained presence beyond Earth.’
 

Palmer GA, Mathyk BA, Jones JA, et al. Reproductive biomedicine in space: implications for gametogenesis, fertility, and ethical considerations in the era of commercial spaceflight. Reprod Biomed Online 2026.
https://doi.org/10.1016/j.rbmo.2025.105431 For more information on this press release and the published paper, please contact:
Duncan Nicholas, RBM Online Development Editor
dev.editor@rbmonline.com RBM Online, founded by the IVF pioneer Sir Robert Edwards, is a widely cited, peer reviewed journal specialising in reproductive science and medicine. END