All of our problems are the result of overbreeding among the working class, and if morality is to mean anything at all to us, we must regard all the … - Margaret Sanger

In passing, we should here recognize the difficulties presented by the idea of 'fit' and 'unfit.' Who is to decide this question? The grosser, the more obvious, the undeniably feeble-minded should, indeed, not only be discouraged but prevented from propagating their kind. But among the writings of the representative Eugenists one cannot ignore the distinct middle-class bias that prevails.

While it is necessary to point out the importance of "heredity" as a determining factor in human life, it is fatal to elevate it to the position of an absolute. As with environment, the concept of heredity derives its value and its meaning only in so far as it is embodied and made concrete in generations of living organisms. Environment and heredity are not antagonistic. Our problem is not that of "Nature vs. Nurture," but rather of Nature x Nurture, of heredity multiplied by environment, if we may express it thus. The Eugenist who overlooks the importance of environment as a determining factor in human life, is as short-sighted as the Socialist who neglects the biological nature of man. We cannot disentangle these two forces, except in theory. To the child in the womb, said Samuel Butler, the mother is "environment." She is, of course, likewise "heredity." The age-old discussion of "Nature vs. Nurture" has been threshed out time after time, usually fruitlessly, because of a failure to recognize the indivisibility of these biological factors. The opposition or antagonism between them is an artificial and academic one, having no basis in the living organism.

Thus we see that the second and third children have a very good chance to live through the first year. Children arriving later have less and less chance, until the twelfth has hardly any chance at all to live twelve months. This does not complete the case, however, for those who care to go farther into the subject will find that many of those who live for a year die before they reach the age of five. Many, perhaps, will think it idle to go farther in demonstrating the immorality of large families, but since there is still an abundance of proof at hand, it may be offered for the sake of those who find difficulty in adjusting old-fashioned ideas to the facts. The most merciful thing that the large family does to one of its infant members is to kill it. The same factors which create the terrible infant mortality rate, and which swell the death rate of children between the ages of one and five, operate even more extensively to lower the health rate of the surviving members.