Clinical Anthropometry in Male Infertility: Differences Between Men With and Without Klinefelter Syndrome

Klinefelter syndrome (KS) is one of the most common genetic causes of male infertility and is frequently associated with characteristic anthropometric features. However, few studies have directly compared body proportions between patients with KS and infertile men without KS in clinical settings in Japan. Therefore, the present study investigated physical characteristics, particularly arm span, in infertile men with or without KS.

The present study included 30 infertile Japanese men with KS and 289 infertile men without KS who visited the outpatient clinic for male infertility at our institution between January 2004 and July 2025. Clinical data included age, height, weight, body mass index (BMI), and arm span.

Arm span was significantly longer in the KS group than in the non-KS group (p = 0.046). Height (p = 0.019) and weight (p = 0.017) were also significantly higher in the KS group, whereas BMI did not significantly differ between the groups.

Infertile Japanese men with KS had a significantly longer arm span than non-KS infertile men, consistent with eunuchoid body proportions. These results underscore the clinical value of incorporating a routine anthropometric assessment, particularly an arm span measurement, in the clinical evaluation of male infertility.