91

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91

910

In eugenics 1, attention is directed primarily to the role of heredity 2, the transmission of human characteristics from generation to generation, operating through genes 3, which are transmitted to children by their parents. The development of eugenic theory is dependent on the progress of genetics 4 (cf. 103-4*), the science concerned with the transmission and effects of hereditary factors. Eugenics as a social movement refers to policies aimed at improving the quality of human populations.

  • 1. eugenics n. — eugenic adj. — eugenist n., a specialist in eugenics. 4. genetics n. — genetic adj. — geneticist n., a specialist in genetics.

911

A distinction has sometimes been attempted between hereditary characteristics 1, which are inherited, and acquired characteristics 2 which are not so transmitted. This is now viewed as a distinction of degree only, because most phenotypic 3 characteristics, i. e., observed characteristics, involve the interaction of both genotypic 4, i. e., inherited factors, and environmental factors. The characteristics determined by a dominant 5 gene (901-3) will appear in all who inherit it; this is not true of a recessive 6 gene. The dominance of a gene, however, may be incomplete or its influence may be masked by other geaes in polygenic action. A lethal characteristic 7 generally brings about the early death of the foetus (602-7). Changes in genes, called mutations 8, are chance variations, and may be pathological in effect. Panmixia 9 is the formation of unions (501-3) at random, i. e., without regard to the affiliation of the parties to genetic groups.

912

A distinction is often made in eugenic policy between positive eugenics 1 aimed at increasing the number of persons believed to have desirable characteristics, and negative eugenics 2 aimed at restricting the reproduction of persons expected to transmit undesirable characteristics or hereditary defects 3. Much attention has been given to the discussion of eugenic sterilization 4, i. e., the sterilization of persons likely to transmit undesirable characteristics to their descendants. Objections to this measure have been raised on moral grounds and also because of its relatively low efficiency in reducing the frequency of recessive genes (911-6). Among the measures proposed, pre-marital examination 5 may be mentioned; this is designed to give couples intending to marry information about the probable quality of their offspring, so that prospective partners to dysgenic marriages 6, i. e., those likely to produce defectives, may be warned.

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back to Introduction | preface | Index
chapters | General concepts index 1 | The treatment and processing of population statistics index 2 | Distribution and classification of the population index 3 | Mortality and morbidity index 4 | Nuptiality index 5 | Fertility index 6 | Population growth and replacement index 7 | Migration index 8 | Economic and social aspects of demography index 9
section | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 20 | 21 | 22 | 23 | 30 | 31 | 32 | 33 | 34 | 35 | 40 | 41 | 42 | 43 | 50 | 51 | 52 | 60 | 61 | 62 | 63 | 70 | 71 | 72 | 80 | 81 | 90 | 91 | 92 | 93