Geographic Differences in Semen Quality among a Cohort of American Men Using Mail-in Sperm Testing Kits

PURPOSE: To evaluate the relationship between regional geography and sperm parameters in a cohort of American men using at-home mail-in semen collection kits with no previous self-reported history of male factor infertility. MATERIALS AND METHODS: In this study, 5,822 men from six different regions of the United States (Northeast, Southeast, Midwest, West, Pacific, and Southwest) who self-requested semen analysis between 2019 and 2021 were enrolled. RESULTS: Across the entire cohort, the mean sperm concentration was 43.79±55.43 ×10(6) sperm/mL; total sperm count 138.93±149.96 ×10(6) sperm/mL; total motile sperm 54.73±81.90 ×10(6)/ejaculate; total motility 30.18%±22.87%; progressive motility 21.61%±17.32%; sperm with normal morphology 8.79%±8.87%. Patients from the West region displayed lower median sperm concentration, total motile sperm, and total motility than men from the other four regional areas. A lower median total sperm count, and lower median progressive motility were also detected among patients in the Southwest region. Conversely, higher results were detected in patients from the Midwest (higher median total motile sperm, total and motility) and from the Northeast (higher median sperm concentration and total sperm count) regions. Men from the Southeast (OR, 1.3168; 95% CI, 1.1142–1.5563) and Southwest (OR, 1.3145; 95% CI, 1.0735–1.6096) regions were more likely to have oligozoospermia than those living elsewhere. CONCLUSIONS: This study provides the most comprehensive and up-to-date report on semen parameter variability among a cohort of men living in six different regions of the continental USA. This study will pave the way into a deeper discussion of the interplay between geography, social determinants of fertility care and semen quality.