Medicine may be reducing the human capacity to survive

It appears that limited natural selection is taking place in populations of developed countries, since most individuals survive and have the full oppo rtunity to reproduce. This paper addresses contemporary natural selection i n a developed country (Australia) using the biological state index. Althoug h the general context of this paper focuses on Australia it can be expected that most other first-world and/or developed countries follow a similar pa ttern. The findings of this study, that 98% of individuals survive through their reproductive period and have the full opportunity to reproduce, suppo rt predictions that natural selection has limited influence on the evolutio n of first-world populations. It appears that first-world populations may n ot be naturally well adapted to their environment but use medical treatment s/technology to increase their survival capacity and maintain fitness. This has two apparent consequences. First, the fitness of individuals will decr ease, since less favorable genes can accumulate in the population, and seco ndly, disease processes will remain fit as they adapt to the selective pres sures exerted by medicine. If medical treatment becomes ineffective, extens ive mortality is expected since fit disease processes will be unleashed on unfit human populations. It appears that a possible answer to these problem s may be found in gene therapy. (C) 2001 Harcourt Publishers Ltd.