Since the 1940s, when gerontology began as a science, ageing has been a contentious subject. Early American and European gerontologists—including Edmund Vincent Cowdry, Valdimiar Korenchevsky, Clark Tibbitts and Nathan Shock—struggled to institutionalise their field, because it was hard to lead people to believe that ageing was a legitimate academic subject with a clear boundary and identity. Ageing was an ambiguous phenomenon, about which little was known. The overlapping domain between ageing and chronic illnesses provoked persistent controversies, while its relation to race, class and gender prompted critical commentators to question the possible or actual bias within the emerging field of gerontology. Furthermore, what gerontologists did to ameliorate the lives of seniors sometimes backfired, as their professional intervention might stigmatise rather than assist the elderly.