Yang B, Sun H, Wan Y, et al. - In this cross-sectional analysis, researchers explored testosterone (T), vitamin D, semen quality, bone mineral density (BMD) as well as their links in Chinese infertile men. Participants included 559 men aged 20–40 years, of these, 195 were fertile men, 9 were infertile men with recognized risk factors for osteoporosis and 355 were infertile men without recognized risk factors for osteoporosis (WOR). A total of 314 oligo-, astheno-, teratospermic or normospermic infertile men and 41 non-obstructive azoospermic men constituted WOR infertile men. In WOR infertile men but not in fertile men, the identified independent determinants of BMD were bioavailable T and 25-hydroxyvitamin D [25(OH)D]. Findings revealed lower T and BMD in infertile men vs fertile men. Low BMD and poor semen quality were observed in infertile men in relation to 25(OH)D and T.