Environmental and microbiome determinants of sperm quality: a narrative review on male health

Traditional and emerging environmental factors synergistically impair male sperm quality through multiple mechanisms, including oxidative stress, endocrine disruption, epigenetic alterations, and systemic inflammation. Future experimental research should shift from single-pollutant studies to real-world mixture exposure investigations, utilizing multi-omics technologies to deeply analyze epigenetic mechanisms and transgenerational effects. Clinically, environmental risk factors should be incorporated into routine screening and counseling for male infertility, with enhanced antioxidant intervention measures. At the policy level, there is an urgent need to improve chemical regulation to prevent potentially stronger reproductive toxicity from novel substitutes and to enhance air pollution control. Curbing the global decline in fertility at its source holds significant importance for advancing population reproductive health.