Garment fit, scrotal thermoregulation, and male fertility outcomes: a narrative review

Scrotal thermoregulation is a recognized feature of normal spermatogenesis, with testicular function occurring at temperatures below core body temperature. Tight-fitting underwear has been hypothesized to influence scrotal temperature, whereas looser garments may allow greater ventilation. Public interest in “fertility-friendly” underwear has increased despite uncertainty regarding clinical relevance. This narrative review synthesizes current literature examining associations between underwear choice, particularly garment fit and fabric, and semen parameters and male fertility outcomes.