EUGENICS 2 3 I 



equipment, has been able to fight his way from the proletariat to the prop- 

 ertied class. Here he marries. There is nothing to guarantee that his wife 

 will be on an equally high level genotypically. Moreover, when his germ 

 cells ripen, segregation, the very principle of Mendelian inheritance, in- 

 sures that this valuable combination of genes is again dissolved, and his 

 genes will enter new combinations in his children. These children may 

 very well be quite ordinary as regards their genotypical quality. 



But, thanks to better nourishment, better opportunities and training, it 

 is much easier for individuals born in an economically independent class 

 environment, even though genetically mediocre, to remain on the social 

 level of their parents, than it is for an individual of superior genotype 

 to overcome the handicap involved in an unfavorable environment with 

 limited opportunities. 



If this is true, this argument against birth control loses its weight. At any 

 rate, an appeal to the intelligent and responsible circles to efTectively in- 

 crease their number of children is futile. The only way open in order to 

 counteract an assumed selective birth rate is accordingly to spread the 

 same information among the poor because every child ought to develop in 

 a good environment. And this goal cannot be attained if we give natural 

 fertility its free course. 



THE ATTITUDE OF THE PHYSICIAN IN QUESTIONS OF 



HEREDITY AND DISEASE 



The individual medical practitioner is most frequently consulted as to 

 the possible consequences of marriage in cases where one or even both 

 partners belong to a family in which the pathological hereditary traits 

 occur. He may, by aid of one of the now existing text-books on the known 

 pathological hereditary traits in man, give valuable advice in quite a few 

 cases. But his judgment should always be given with the reservation in- 

 volved in the fact that genetics primarily deals with probabilities. 



A frequent question is whether a normal person belonging to a family 

 in which a recessive pathological trait occurs may be expected to beget 

 affected children if he marries an unrelated individual. This must of 

 course be answered in the negative. As regards serious dominant ab- 

 normalities we have presented quite a few cases where affected heterozy- 

 gous carriers should be advised against propagation, even though the 

 chance of begetting an unaffected child is i: i. If such an individual never- 

 theless takes the chance and begets a normal child, then further propaga- 

 tion should be prevented. 



Intermarriage in famihes where dominant pathological traits occur is 

 generally inadvisable. In families where serious recessive pathological 

 traits are met with, such as extreme eye abnormalities and hereditary types 

 of deafness, the risk involved in an intermarriage of two normal, but pos- 

 sibly heterozygous family members should be made clear to the consultants. 



