eugenics

eugenics A postulated method of improving humanity by altering its genetic composition. It would involve encouraging the breeding of those presumed to have desirable genes (positive eugenics), and discouraging the breeding of those presumed to have undesirable genes (negative eugenics). It relies upon the notion of ‘desirable’ and ‘undesirable’ genotypes and assumes that selection for these can be particularly applied. Neither concept is generally accepted as valid, the former because it is often a value judgement that will vary between individuals, societies, and circumstances; the latter because genotypes are often present in the heterozygous state and so are not readily detected. Every human is heterozygous for several different deleterious recessive genes, so that if these were detectable, no one would be allowed to breed under such a programme.