A new international study warns that reproductive health in space is no longer a theoretical concern and that questions about fertility and pregnancy should be pressing concerns.
As commercial spaceflight edges closer to reality, astronauts spend more time orbiting Earth, and as we look to one day settle on Mars, questions about sex and reproductive health in space need to be urgently addressed, experts say.
Published in the peer-reviewed journal Reproductive Biomedicine Online, a new international report brings together experts in reproductive medicine, aerospace science and bioethics to warn that the rapid expansion of human activity in space is outpacing policies designed to protect reproductive health.
More than 50 years ago, "two scientific breakthroughs reshaped what was thought biologically and physically possible - the first Moon landing and the first proof of human fertilisation in vitro," said clinical embryologist Giles Palmer from the International IVF Initiative.
"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," he added.
The complications of reproduction in space
Despite advances in assisted reproductive technologies (ART), such as IVF and ICSI, there are still no widely accepted, industry-wide standards for managing reproductive health risks in space.
Risks include inadvertent early pregnancy during missions, the effects of radiation and microgravity on fertility, and the ethical boundaries around any future reproduction-related research.
Evidence from lab studies and limited human data suggests that space - described in the report as "an increasingly routine workplace" - is nevertheless "a hostile environment" for human biology.
"Microgravity, cosmic radiation, circadian disruption, pressure differentials, and extreme temperatures found in orbit" are all factors known to interfere with healthy reproductive processes in both men and women.
Animal studies indicate that short-term radiation exposure can disrupt menstrual cycles and increase cancer risk. However, the review highlights a lack of reliable long-term data from male and female astronauts after extended missions.
Reproductive tissues are especially vulnerable to DNA damage, the study notes, and the impact of cumulative radiation exposure on male fertility during long missions remains what the authors call a "critical knowledge gap."
Could IVF work in space?
So far, no human has ever conceived or given birth in space and pregnancy is still a strict contraindication for those travelling beyond Earth.
Yet the study notes that automated fertilisation and cryopreservation technologies 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," said 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."
The authors of the report argue that ethical questions surrounding human reproduction in space can no longer be deferred.
“As human presence in space expands, reproductive health can no longer remain a policy blind spot,” said Dr Fathi Karouia, a 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."