The Science of Eugenics v
Eugenics and the Power of Heredity
The eugenic marriage, when it comes, will be based upon the principles and knowledge of heredity. When a young man and a young woman, offering themselves for marriage, can produce certified records of their ancestry back for three or four generations, showing that their progenitors have been entirely, or largely, free from nervous prostration, sick headaches, neurasthenia, hysteria, melancholia, St. Vitus' dance, epilepsy, syphilis, alcoholism, pauperism, criminality, prostitution and insanity - when they can further show that their ancestors have been free from all other inheritable forms of nervous disorders, including certain forms of deafness, color blindness and other indications of defectiveness and degeneracy, then it may truly be said that such a union may be correctly styled a eugenic marriage.
The Eugenic Marriage
It should be further understood that the new science of eugenics clearly teaches that many of these nervous and other defective traits, which are directly inheritable, are what biologists call "mendellian[sic] recessives", i.e., that when any person so afflicted marries one not so afflicted, that the majority of these traits tend to disappear -- to "Breed out" of their offspring.
The Law of Posterity
Eugenics thus brings encouragement to every member of the human race to seek in its mating to set a higher standard for the succeeding generation. This is illustrated by the fact that if a young woman with tendencies toward feeble-mindedness marries a strong minded man, some or all of the children are likely to be more normal-minded than the mother, whereas, if the feeble-minded girl marries a feebleminded man, practically all of the children are doomed to be feeble-minded.