This article compares the motivations for, and responses to, castration between two groups of males: prostate cancer patients and voluntary modern-day eunuchs with castration paraphilias or other emasculating obsessions. Prostate cancer patients are distressed by the side effects of androgen deprivation and typically strive to hide or deny the effects of castration. In contrast, most voluntary eunuchs are pleased with the results of their emasculations. Despite a suggested association of androgen deprivation with depression, voluntary eunuchs appear to function well, both psychologically and socially. Motivation, rather than physiology, appears to account for these different responses to androgen deprivation.