With increased recognition of the benefits of testosterone (T) therapy for middle-aged men, there has been a concomitant reexamination of the historical fear that raising T will result in more prostate cancer (PCa). Studies have failed to show increased risk of PCa in men with higher serum T, and supraphysiologic T fails to increase prostate volume or prostate-specific antigen in healthy men. This apparent paradox is explained by the Saturation Model, which posits a finite capacity of androgen to stimulate PCa growth. Modern studies indicate no increased risk of PCa among men with serum T in the therapeutic range.