After stratification according to age (≤ 50 yrs vs. > 50 yrs), participants over 50 yrs had a significantly higher PSA level (1.0 ng/ml vs. 0.7 ng/ml, p < 0.01) and had more frequently at least one prior prostate cancer checkup in the past (42.0 vs. 12.1%, p < 0.01). This evidence concerns the gene KLK3 and Familial prostate cancer.