Using Surveillance, Epidemiology, and End Results patient cases and controlling for aging of the population, we found the median age and prostate-specific antigen (PSA) level at prostate cancer diagnosis increased by 1.4 years of age (95% CI = 1.3 to 1.5 years) and 1.4 ng/mL (95% CI = 1.4 to 1.5 ng/mL) over this period, consistent with the delayed detection hypothesis. This evidence concerns the gene KLK3 and prostate cancer.