Advancements in sperm selection and assessment: traditional to cutting-edge methods in assisted reproductive techniques – a narrative review

Infertility affects approximately 15% of couples globally, with male factors contributing to 20-70% of cases. These issues often stem from low sperm concentration, abnormal morphology, or poor motility, highlighting the critical importance of sperm selection in both natural and assisted reproduction. The quality of selected spermatozoa impacts not only fertilization success but also the health of future offspring. Despite the advances in in vitro fertilization, no universally accepted method exists for selecting and assessing spermatozoa based on morphology, motility, and DNA quality. Over the past decade, significant progress has been made in sperm selection technologies, aimed at enhancing fertilization efficiency. Traditional methods are now complemented by innovative technologies like microfluidics and artificial intelligence, enabling more precise sperm data analysis. These tools improve the identification of the most fertile spermatozoa while reducing the risk of reproductive failures. Additionally, advancements in mathematical and computational modeling have enhanced our ability to simulate and predict sperm selection processes. These models incorporate crucial factors, offering deeper insights into sperm quality and behavior. This review discusses the current methods and devices used for sperm selection and assessment, recent trends in modeling these processes, and potential future directions. By analyzing the latest scientific literature, we explore how emerging technologies impact the effectiveness of sperm selection. These advancements hold promise for improving reproductive outcomes and developing innovative clinical and biotechnological tools.