Abstract
Sperm DNA fragmentation is an important functional marker of male fertility that complements conventional semen analysis and reflects damage to gamete genetic material. This review aimed to summarize current evidence on biological, clinical, behavioral, and environmental factors associated with increased sperm DNA fragmentation. Professional guidelines, systematic reviews, meta-analyses, and key original studies indexed in PubMed , Scopus , and Web of Science were analyzed. Chromatin remodeling disorders, oxidative stress, apoptosis, impaired sperm maturation, and the effects of age, varicocele, inflammation, infections, metabolic disorders, cancer, fever, smoking, alcohol consumption, obesity, physical activity, sexual abstinence, heat exposure, and environmental pollutants were considered. The most consistent associations were identified for varicocele, severe oxidative stress, smoking, advanced age, and certain toxic exposures. Laboratory and threshold heterogeneity limits direct comparisons. Clinical interpretation should consider the analytical method, patient history, and modifiable risk factors.