BACKGROUND: The ratio of digit lengths is fixed in utero, and may be a proxy 
indicator for prenatal testosterone levels.
METHODS: We analysed the right-hand pattern and prostate cancer risk in 1524 
prostate cancer cases and 3044 population-based controls.
RESULTS: Compared with index finger shorter than ring finger (low 2D : 4D), men 
with index finger longer than ring finger (high 2D : 4D) showed a negative 
association, suggesting a protective effect with a 33% risk reduction (odds 
ratio (OR) 0.67, 95% confidence interval (CI) 0.57-0.80). Risk reduction was 
even greater (87%) in age group <60 (OR 0.13, 95% CI 0.09-0.21).
CONCLUSION: Pattern of finger lengths may be a simple marker of prostate cancer 
risk, with length of 2D greater than 4D suggestive of lower risk.