As space missions extend in duration, the impact of spaceflight on human reproduction poses serious biomedical challenges. The reproductive system is susceptible to microgravity, ionizing radiation, and circadian disruption. This review summarizes current evidence on how space environments affect reproductive function, focusing on gametogenesis, hormonal regulation, pregnancy, and embryonic development. We reviewed data from rodent models, parabolic flight experiments, and space-exposed cellular systems to assess the effect of space-relevant stressors on reproductive health. Findings show that microgravity impairs sperm motility and hormonal balance, while radiation increases DNA fragmentation and induces heritable epigenetic changes. Female reproductive health is similarly affected, with radiation accelerating follicular loss and hormonal disruption impairing ovulation. Early pregnancy stages, including implantation and placental development, are especially vulnerable to space conditions. Rodent studies indicate that while basic fertility may persist, the long-term effect on offspring health and multi-generational outcomes remains unclear. These findings highlight the need for targeted countermeasures and continued research to ensure reproductive success in future space missions.

ABSTRACT
INTRODUCTION
MAIN BODY
    Effects of spaceflight on the male reproductivesystem
    Effects of spaceflight on female reproductive system
    Pregnancy and embryonic development in space
    Future direction for research
CONCLUSION
REFERENCES

• Byeonggyu Ahn(Department of Physiology, College of Medicine and Institute of Medical Sciences, Gyeongsang National University, Jinju 52727, Korea, Department of Convergence Medical Science, Gyeongsang National University, Jinju 52727, Korea)
• Jina Ha(Department of Physiology, College of Medicine and Institute of Medical Sciences, Gyeongsang National University, Jinju 52727, Korea, Department of Convergence Medical Science, Gyeongsang National University, Jinju 52727, Korea)
• Dawon Kang(Department of Physiology, College of Medicine and Institute of Medical Sciences, Gyeongsang National University, Jinju 52727, Korea, Department of Convergence Medical Science, Gyeongsang National University, Jinju 52727, Korea) Corresponding author