Abstract
Over the past four decades, reports have emphasized the spatial and temporal trends in human semen quality and other markers of male reproductive health, which have sparked significant debate among fertility professionals. This trend appears limited to specific geographical regions rather than being global. The study aimed to retrospectively review the comprehensive distribution of semen characteristics and analyze their temporal changes over a period of 17 years at a single center in the southern parts of India. Ejaculates of 12,151 sub-fertile men undergoing infertility workup at the University Andrology Laboratory from 2006 to 2022 were included. Semen analysis was performed as per the World Health Organization (WHO, 1999, 2010) recommendations. The primary outcome of interest was temporal changes in semen parameters, whereas data regarding the distribution of semen characteristics were also measured. Sperm concentration, total sperm number, motility, vitality, and morphology showed no significant variations over time. The fifth percentile of semen volume, sperm concentration, total motility, vitality, and normal morphology were 0.5 mL, 1.5 million/mL, 21.0%, 28.0%, and 7.0%, respectively. This study revealed no temporal decline in sperm concentration, motility, and morphology in 17 years, and found fifth percentile sperm characteristics were lower than WHO reference values, marking the extensive long-term semen quality analysis from a single Indian laboratory. The findings reported here do not support an alarming temporal decline in semen quality.