Abstract Introduction: Future human exploration of the Moon, Mars, and other deep-space destinations raises questions regarding human reproductive capacity in extraterrestrial environments. Prolonged exposure to microgravity, cosmic radiation, isolation, and chronic stress can alter the function of the hypothalamic-pituitary-gonadal axis, leading to hormonal changes that could impact male and female fertility. Although human reproduction in space has not yet been directly studied, research using animal models and physiological studies on astronauts suggests that space conditions could affect the production of testosterone, estrogens, and gametes, posing a challenge for future multigenerational missions. Objective: To analyze available evidence regarding reproductive endocrine alterations associated with the space environment and to discuss their implications for human fertility in scenarios of extraplanetary colonization. Methodology: A narrative review of the scientific literature concerning reproductive endocrinology, space medicine, and reproductive biology was conducted. The review includes studies involving astronauts, animal models exposed to actual or simulated microgravity, and experiments regarding space radiation and gonadal function. Results: