Why do men go bald with age? In normal men, advancing age is accompanied by an increase in the incidence and extent of baldness. In eunuchs castrated prepubertally and given androgen treatment in the second decade of life, hair was lost slowly over a period of years, resulting in hair loss similar to noncastrated men of the same age. In contrast, the eunuchs who had reached the sixth decade of life before receiving androgens lost hair within a few months after beginning the treatment. Evidently the susceptibility to alopecia increases with age but is not expressed in the absence of inciting agents such as androgens (Hamilton 1942).