The finite lifetime of cultured normal human and animal cells has significant implications that bear on our understanding of the fundamental biology of aging. An assessment of the goals of biological research in gerontology leads to the conclusion that, unlike successes in disease-oriented research, advances that will allow us to tamper with our biological clocks could result in serious societal dislocations. Nevertheless, the probability that this may occur is slight, in view of the shrinking support underpinning research in aging.