The Player was a rather old man
The Player was a rather old man, extremely unusual on Gor, where the stabilization serums were developed centuries ago by the Caste of Physicians in Ko-ro-ba and Ar, and transmitted to the Physicians of other cities at several of the Sardar Fairs. Age, on Gor, interestingly, was regarded, and still is, by the Castes of Physicians as a disease, not an inevitable natural phenomenon.
The fact that it seemed to be a universal disease did not dissuade the caste from considering how it might be combated. Accordingly the research of centuries was turned to this end. Many other diseases, which presumably flourished centuries ago on Gor, tended to be neglected, as less dangerous and less universal than that of aging. A result tended to be that those susceptible to many diseases died and those less susceptible lived on, propagating their kind.
Assassin of Gor, p. 44