ABSTRACT
<p><b>OBJECTIVE</b>To investigate the relationship between the second to the fourth digit ratio (2D:4D) and body mass index (BMI) in infertile men of the Han ethnic group in Ningxia.</p><p><b>METHODS</b>Using anthropometry, we calculated the mean ratio of 2D:4D and BMI of 197 infertile men and 148 normal healthy male controls, followed by analysis of their relationship.</p><p><b>RESULTS</b>The BMI was correlated positively with the 2D:4D ratio of the left hand in the infertile men (P < 0.05) and in the patients with a higher 2D:4D ratio of the left hand (P < 0.05), but negatively with the 2D:4D ratio of the righ/left (Dr-1) (left: P < 0.01; Dr-l: P < 0.05). The mean 2D: 4D ratio and BMI were both lower in the normal control than in the infertile men, with statistically significant differences in BMI (P < 0.05) and the 2D:4D ratio of the left hand (P < 0.05).</p><p><b>CONCLUSION</b>There is a correlation between the 2D:4D ratio and BMI in infertile men.</p>