Racial Differences in Semen Quality: A Systematic Review and Meta-Analysis of Semen Parameters

Abstract

Racial and ethnic differences in semen quality are crucial for understanding disparities in male reproductive health and infertility, yet these variations remain underexplored in the global context. We assess racial differences in semen quality, including key parameters, such as sperm concentration, motility, morphology, and total sperm count, while comparing outcomes between fertile and infertile groups, and examining variations across geographic regions and socioeconomic contexts, including comparisons between high-income and middle-income countries. A comprehensive search of PubMed, Embase, Scopus, and Web of Science was conducted for studies published from 1985 to 2024. Semen parameters included semen volume, sperm concentration, total sperm count, sperm motility, progressive motility, viability, and morphology. Data from 40 studies comprising 71,880 samples were synthesized using a random-effects meta-analysis, following PRISMA guidelines. Asians exhibited the highest sperm concentration (53.79 million/mL) and motility (54.97%), while Blacks showed the lowest values in sperm morphology (7.85%) and total sperm count (78.04 million). Fertile groups consistently outperformed infertile groups across all parameters, with significant declines in motility and morphology in the infertile population. ANOVA and Tukey post hoc tests confirmed significant intergroup differences. This study highlights substantial racial differences in semen quality, influenced by genetic, environmental, and socioeconomic factors. The findings emphasize the need for culturally tailored interventions and future research to address global disparities in male reproductive health.