The Role of X and Y Chromosomes in Semen Morphology and Concentration: A Study in Saran, Bihar, India

Abstract

This study investigates the age-related variations in body mass index (BMI), ethnicity, abstinence time, smoking status, and sperm quality among men from Saran, Bihar, across six age groups (20–50 years). BMI demonstrated a progressive increase with age, ranging from 22.5 ± 1.5 kg/m² in the youngest group (20–25 years) to 28.5 ± 2.0 kg/m² in the oldest group (46–50 years), highlighting a trend of increasing weight with age. Ethnic distribution revealed a predominance of Hindus across all groups, with a decline from 75% in younger men to 50% in older individuals, accompanied by a proportional increase in Muslims. Abstinence time showed notable age-related variations, with shorter abstinence periods (≤2 days) more common in younger participants, and longer periods (≥5 days) more prevalent in older groups. Smoking behaviour exhibited a marked shift, with the percentage of never-smokers decreasing from 62.5% in the youngest group to 30% in the oldest, while the prevalence of current smokers increased correspondingly. Sperm quality analysis revealed significant age-related declines in sperm concentration (from 45 ± 5 million/mL to 15 ± 3 million/mL), normal morphology (from 75% to 50%), and motility (from 80% to 40%). Chromosome distribution analysis indicated a strong correlation between higher proportions of Y-chromosome-bearing sperm and better semen quality. Younger age groups, characterized by higher percentages of Y chromosomes (56% in Group A), exhibited superior sperm concentration, morphology, and motility, while older groups with reduced Y-chromosome proportions (49% in Groups E and F) showed deteriorated semen parameters. These findings underscore the combined impact of aging, lifestyle factors, and chromosomal distribution on male fertility. The study highlights the potential of Y-chromosome dominance as a biomarker for assessing semen quality, emphasizing the need for early health interventions to preserve reproductive health in men.