RESULTS: African-American men with prostate cancer are 3.70 times more likely to have a low 2D:4D digit ratio than Caucasian men with prostate cancer (95% confidence interval: 1.98, 6.92; P < 0.0001). There were no statistically significant differences in the presence of metastasis, Gleason score, family history or age at diagnosis by digit ratio. CONCLUSION: 2D:4D ratio shows strong differences between African-Americans and Caucasians; however, it does not correlate with disease severity in men already diagnosed with prostate cancer.