The Hydra and its Many Heads
by Garland E. Allen

The June 15, 2006 issue of the New York Times carried the headline, “That Wild Streak? Maybe It Runs in Your Family.” The gist of the article was stated in its opening sentences: “Jason Dallas used to think of his daredevil streak — a love of backcountry skiing, mountain bikes and fast vehicles — as ‘a personality thing.’ Then he heard that scientists at the Fred Hutchinson Cancer Research Center in Seattle had linked risk-taking behavior in mice to a gene. Those without it pranced unprotected along a steel beam instead of huddling in safety like the other mice... ‘It’s in your blood,’ Mr. Dallas said. ‘You hear people say that kind of thing but now you know it really is.’” Well, there you have it — the reasoning and the consequences of the widespread public dissemination of ideas about genetic determinism all wrapped up together. Optimists, who think that simplistic ideas about what genes can and can’t do have become better understood, are brought back to the reality of the continued resurgence of genetic determinism in the media. Like the mythical Hydra, new heads emerge from those that are shorn off in a seemingly endless sequence of new and sensational claims.

There are many examples, both contemporary and historical, that can illuminate current thinking about genetic determination of human behaviors. They emphasize what is wrong, biologically, with the very concept of genetic determinism, the flaws behind its fundamental claims. They also emphasize the social harm that can arise, and indeed has arisen, from widespread acceptance of such ideas. Finally, they suggest how, from recent studies growing out of the Human Genome Project, we are coming to a more plastic concept of the genome and how genes function. All of this is necessary in combating the resurgence of genetic determinism represented by the New York Times article quoted above.

The field of history and philosophy of science is uniquely positioned to help understand the origin and continued recurrence of genetic determinist ideas, as well as to provide strong arguments for why we must oppose them. At the present time, genetic determinist arguments have the potential for influencing a variety of legislative programs, from eligibility for health care insurance to civil rights laws based on race, gender and sexual orientation. If, for example, insurance companies can use genetic arguments to refuse policies, or charge higher premiums, or require abortion of a fetus claimed to have a behavioral genetic disorder, then it is imperative for the scientific community to become proactive and expose the lack of any clear evidence on which such policies could be based.

I’d like to begin with a summary of points I think we need to keep in mind in combating genetic determinist arguments, in short, what we are not saying, as well as what we are saying about the relationship between genes and behavior. This is followed by a brief review of how belief in genetic determinism — focused primarily in the eugenics movement between 1900-1945 — functioned economically and politically, as a way to combat increasing social disaffection and tension in the larger society. I will conclude with an analysis of what I see as the cause for the continued resurgence of genetic determinist ideas, as a way to deflect anger and frustration arising from the exploitative working conditions of Gilded Age industrialization.

Behavior Genetics As A Field of Research

From Darwin and various instinct theorists onward, there has been a general recognition that some forms of behavior are passed on to successive generations. The field of behavior genetics has developed some highly sophisticated studies of animal behavior during the twentieth century. The behaviors that are most relevant to these studies have tended to be clearly defined and ritualized, such as courtship and reproductive behavior, parental feeding and defense, bird or cricket songs, spiders’ web construction, and primate sociality, to name a few. Some, such as the hygienic and unhygienic hive cleaning behavior of bees, have even been shown to follow simple Mendelian rules of inheritance. The clarity with which these behaviors have been elucidated, however, is the result of their being amendable to rigorous, experimental analysis. These studies have demonstrated that (1) rather intricate behaviors can be genetically programmed to a highly specific degree — thus there is no inherent reason to suppose, from a biological point of view, that behavior cannot be genetically controlled to some extent; (2) virtually all behaviors involve some cue or input from the environment for full development to occur (for example, many bird songs are genetically controlled, but individual birds must hear the song once or twice before executing it perfectly themselves); and (3) every specific type of behavior has to be studied on its own to understand how heredity and environment interact to produce the adult condition. It is not possible to make predictions about behaviors in one species from analogies to what seems like a similar behavior in other species (for example, the similarity in facial expression between dogs, apes and humans may not necessarily reflect similarity of feeling or intended behavior).

It is important to emphasize, however, that most of these methodological problems have been put forward for nearly 80 years in response to the various incarnations of genetic determinist claims, and continue to plague studies that purport to have advanced beyond earlier “crude” explanations during the eugenics era. Something other than scientific claims must account for the continual dishing up of the same old arguments in favor of behavior genetics. Here is where I think history can help our understanding.

The Dangers of Genetic Determinism: A Lesson from History

In the early twentieth century (roughly 1900-1945) a widespread movement in the United States and Europe, known as eugenics, was making similar strong claims as those we encounter today about the genetic basis of human behavioral and personality traits. Eugenicists based their hereditarian claims on the then-new, exciting science of Mendelian genetics, which like molecular genetics today, was making great strides in understanding basic genetic mechanisms. Their claims had a far-reaching impact on legislation in a number of countries, including the United States, Scandinavia, and, most of all, in Germany after the Nazi take-over in 1933. The historical development of the eugenics movement can provide some useful lessons for us today.
Eugenics was a term coined in 1883 by Francis Galton, a geographer, statistician, and cousin of Charles Darwin. It referred to “the right to be well-born” or, in the words of Galton’s foremost American disciple, Charles B. Davenport, the “science of human improvement by better breeding.”[1] Eugenics dominated much of the social reform thinking that abounded in the first four decades of this century. Eugenicists argued that many social problems could be eliminated by discouraging or preventing the reproduction of individuals deemed genetically unfit, while desirable social traits could be increased by encouraging reproduction among those deemed most genetically fit. Eugenicists thought of themselves as bringing the latest scientific research to bear on old and previously unsolved social problems, including criminality, violent behavior, alcoholism, “pauperism,” sexual deviancy, feeblemindedness and manic-depressive insanity.

Many eugenicists had an interest in agricultural breeding and thought of their work as extending the knowledge of animal husbandry to improving the human species in much the same way as a breeder improves a flock or herd. “The most progressive revolution in history could be achieved,” Charles B. Davenport wrote in a letter of 1923, “if in some way or other human matings could be placed on the same high plane as...horse breeding.”[2] Like the breeder, the eugenicist used pedigree analysis to determine the hereditary make-up of family lines; but unlike the breeder, the eugenicist could not use controlled mating experiments to test conclusions drawn from pedigree analysis. Hence, social transmission and biological transmission were conflated.

Much of the research work was carried out or organized through the Eugenics Record Office (ERO) at Cold Spring Harbor, Long Island. The ERO was the institutional nerve center of North American eugenics; it was directed by Davenport and funded by the Harriman family of New York until 1916. At that time it was taken over by the Carnegie Institution of Washington, and maintained until its final closure in 1940. The Eugenics Record Office was managed by Davenport’s enthusiastic minion Harry Hamilton Laughlin, who was recruited in 1910 from a teaching position at an agricultural and teacher-training school in northeastern Missouri.[3,4] Besides the ERO, many other eugenics organizations existed in the U.S., including state branches of the nation-wide American Eugenics Society, the Race Betterment Foundation (funded by the Kellogg cereal family in Battle Creek, Michigan) and the Human Betterment Foundation in Pasadena, California.

The Social and Political Agenda of Eugenics

Beyond research, eugenicists were also interested in social action, including education and popularization of eugenics, and working to pass laws that would promote eugenic goals. Eugenics became incorporated into most major high school textbooks from the 1920’s well into the 1950’s.[5] The picture that emerged for even the most casual reader was that eugenics represented the cutting edge of modern science, the application of rational scientific principles to the solution of what had been seen as intractable social problems. Gone were the ineffective charity and social work programs that eugenicists were convinced only perpetuated pauperism, criminality and alcoholism, because they did not touch the source of the problem — bad genes. Indeed, charity and public handouts, according to eugenics literature, only increased the problem by enabling the degenerate segments of the population to have more children.
Eugenicists were especially active in the United States in areas of immigration restriction (1921, 1924) and in the enactment of state eugenic sterilization laws (1907-1940’s). On the immigration issue, eugenicists were convinced that the newer immigrants coming to the United States after 1880, mostly from central and southern Europe, and the Balkans, Russia and Poland, were biologically inferior (the “dregs of humanity” as one eugenic pamphlet put it) to the older Anglo-Saxon and Nordic stocks, whose immigration had flourished in the first half of the century. Laughlin and others carried out studies purporting to show the high rate of “pauperism,” feeblemindedness, criminality and other deleterious traits — claimed to be genetic in origin — that existed in various immigrant groups. Laughlin took his findings to Congress, where he appeared as the official “Eugenics Expert Witness” to the House Committee on Immigration and Naturalization, whose Chairman, Representative Albert Johnson of Washington State, was an enthusiastic eugenicist who several years prior, had been appointed Honorary President of the Eugenics Research Association. Laughlin’s data, such as his comparison of rates of incarceration for criminal behavior among different national groups, were designed to convince the House Committee that scientific evidence, not ethnic bias or political expediency, made such immigrant groups a bad risk.

The objective cover of science had considerable political appeal to the legislators. The Reed-Johnson Act passed both houses of Congress in 1924, and was signed into law by President Calvin Coolidge, acting on his earlier assertion that “the country cannot have too many inhabitants of the right kind.”[6] The Reed-Johnson Act had drastic consequences, including turning back boats bringing refugees from Nazi Germany in the mid- and late- 1930’s because of the “quotas” it established.

Eugenicists were also instrumental in lobbying for the passage of compulsory sterilization laws at the state level. Articles in newspapers and popular magazines emphasized the cost to the average citizen of maintaining degenerate and inferior people and their children at state expense. Laughlin drew up a “Model Sterilization Law” that was sent to all state legislatures. The results were successful: by 1935 thirty states had enacted laws that allowed inmates of state institutions (prisons, insane asylums, sanitariums and mental hospitals) to be forcibly sterilized after examination by a “Eugenics Committee.”[7] “Habitual criminality,” “sexual perversion,” “low moral sense,” “hereditary feeblemindedness” and epilepsy were all categories that could lead to compulsory sterilization. By 1935, over 21,000 eugenically motivated sterilizations had been performed, and it has been estimated that more than 64,000 people had been sterilized in the U.S. alone by the early 1960’s.[8] Sweden carried out almost the same number in the same time period, while the Nazi sterilization law, passed in 1933, eventually led to the sterilization of over 400,000 people in Germany. In the political arena, eugenics was used to promote or justify social policies that conformed to common prejudices about racial and ethnic minorities, and the drain they supposedly were exerting on society at large.

Criticism of Eugenics

There was opposition to eugenic claims, starting in the early and mid-1920’s in both the United States and Europe. Among biologists, Herbert Spencer Jennings, Raymond Pearl, H.J. Muller and T.H. Morgan all wrote about the extravagant claims made in the name of eugenics, and on the lack of rigor in the analysis of eugenic data. Some sociologists, such as Henry Ward, noted the lack of any real discussion of economic, political and environmental factors in the writings of many eugenicists. And journalist Walter Lippman wrote a series of scathing attacks in the New Republic in the fall of 1922 on the claims of a genetic basis of I.Q.9 Many Catholics opposed eugenics on general doctrinal grounds, and in 1930, Pope Pius XI put forward the encyclical Casti Connubii, which contained language specifically directed at the eugenics movement and its emphasis on sterilization. In the same year, the Soviet Union banned eugenics and eugenics organizations as gross manifestations of the perversion of bourgeois science.
Biologists of that time criticized eugenics on all the major methodological points with which we are familiar today: vague definition of behavioral categories, subjective/biased and sloppy collection of family pedigree data, failure to take into account the role of the environment in development, biased sampling of study populations and faulty analysis of data. A few select examples of these criticisms will indicate the extent to which the problems inherent in this research were apparent at the time. They will also serve as a chilling reminder of how little research purporting to show genetic basis for behavior has really advanced in the past 80 years.

On the problem of defining complex behavioral phenotypes and separating out the supposed genetic from environmental input, Thomas Hunt Morgan leveled a series of criticisms at eugenics starting in 1925. He chastised eugenicists for lumping many mental and behavioral conditions together under a vague rubric like “feeblemindedness” and treating it as if it necessarily derived from a single underlying cause (the problem of reification, as we would term it today).

He also noted that it was virtually impossible to separate the effects of heredity from those of environment in the development of human traits because we cannot carry out rigorous experiments and raise the offspring under precisely controlled experimental conditions. Especially critical, he noted, was the fact that personality and social traits were the most malleable of our characteristics, and hence the most difficult in which to tease apart the relative contributions of heredity and environment.

The pedigree charts on which Mendelian analyses were based were themselves strongly criticized by Morgan and others as giving the impression of tracing genetically determined transmission when, of course, they equally well could be interpreted as showing culturally-determined transmission:

The pedigrees that have been published showing a long history of social misconduct, crime alcoholism, debauchery and venereal disease are open to the same criticism from a genetic point of view; for it is obvious that these groups of individuals have lived under demoralizing social conditions that might swamp a family of average persons. It is not surprising that, once begun from whatever cause, the effects may be to a large extent communicated [socially] rather than inherited [genetically].[10]

Pedigree charts do not separate “nature” from “nurture.” This point is illustrated by Davenport’s study of the inheritance of pellagra, a serious physiological condition in the early twentieth century caused, as we now know, by a vitamin deficiency.[11] Using family pedigree studies Davenport showed what looked like strong hereditary transmission of pellagra within families. The causal agent, of course, was socially-transmitted patterns of poverty and poor nutrition, not genes.[12]

Critics in the 1920’s and 1930’s were well aware of another problematical method in eugenic data: the use of twins (identical raised together, identical raised apart, fraternal compared to identical, etc). Again, Morgan made the point very clearly:

The very close physical similarity of twins of this kind might make such material favorable for study [of heredity of mental traits]. There are, however, even here two serious drawbacks that complicate the results. In the first place, unless the twins had been separated in very early childhood it would be difficult to decide how much is due to similarity of nature and how much to nurture. A comparison with other children in the same family may be helpful but is not decisive, for the experience of each child from successive births is affected by older and younger children in the family. Until these difficulties can be overcome, the many anecdotes of the close similarity in temperaments, or abilities, of identical twins do not supply the needed evidence.[13]

An equally public attack on eugenics came in 1926 from Raymond Pearl at Johns Hopkins University.[14] Pearl, and his colleague Herbert Spencer Jennings, both agreed with basic eugenic principles, but felt that propagandists like Laughlin, Madison Grant and others made claims that went far beyond any reasonable evidence.[15] Both were also struck by the pejorative tones used to describe the supposed biological inferiority of immigrants during the Congressional debates. H.J. Muller, a student of Morgan’s, and later himself to become a Nobel laureate in genetics, argued that until the economic and social environment could be equalized it would be impossible to know how much of any individual’s “social inadequacy” was due to heredity and how much to environment.[16] Much of feeblemindedness might be due to poor maternal diet during pregnancy or during the early years of childhood, or to maternal drug and alcohol use; although these effects might appear at a superficial glance to be genetic, they had nothing to do with defective genes.

Physiological chemist Oscar Riddle argued that eugenicists were “developmentally blind.” Riddle had worked on endocrine function, particularly the role played by hormones in growth and development, and was sensitive to the apparent disregard most eugenicists had for the role of the environment in the development of mental and behavioral traits in humans. In his view, genes were not rigid determiners, but their output, whatever it was, could be significantly influenced by external factors:

It has become clear that the specific conditions under which a gene or factor operates and develops have an equal value with the germinal factors in the appearance of anything that can be called heredity.[17]

Herbert Spencer Jennings emphasized the same lack of appreciation for developmental aspects of genetics. Jennings approached the problem of heredity from a more holistic and integrative position than most of his contemporaries, and hence to him the oversimplifications of the eugenicists seemed particularly outmoded and dangerous. In a 1927 critique of eugenics, Jennings found the lack of consideration of gene-environment or gene-gene interactions in the writings of eugenicists not only naive, but just plain wrong. A few years earlier he had made the interactionist point the focus of an essay on “heredity and environment”:

[N]ot only what the cell within the body shall become, but what the organism as a whole shall become, is determined not alone by the hereditary materials it contains, but also by the conditions under which those materials operate. Under diverse conditions the same set of genes will produce very diverse results. It is not true that a given set of genes must produce just one set of characters and no other...It is not true that what an organism shall become is determined, foreordained, when he [sic] gets his supply of chemicals or genes in the germ cells, as the popular writers on eugenics would have us believe. The same set of genes may produce many different results, depending on the conditions under which it operates.[18]

The most comprehensive and devastating critique of the whole range of eugenic claims was published by the American Neurological Association in the mid-1930’s, a few years after the appearance of a similar critique, the Brock Report, in Britain. The authors argued that we do not know “enough about the mental diseases and the effects of the social structure to manipulate in a successful way the procreation of the race.”[19] The level of genetic knowledge was too slight to formulate any social policies or carry out any specific manipulations guaranteed to alter the genetic basis of future generations.

Eugenics and its Economic, Social and Political Context

If the obvious pitfalls of eugenics were so apparent to contemporary biologists, why did the movement persist into the 1930’s with any scientific credibility? The answer to this question is complex, and there are several possible reasons. Clearly, one is that many of the opponents did not rouse themselves into active opposition until the mid- and late-1920’s. This activity was largely spurred on by the considerable publicity given to the immigration debates and the racist statements made, in the name of eugenics, about the “undesirable” immigrant groups that were arriving in such large numbers. The eugenicists were distinctly more pro-active than their opponents until well into the 1920’s. By then, and given the largely academic forum in which opponents published their critiques, the biologists came on too little and too late. The promotion of eugenics itself, from the outset, served a far more widespread social and political purpose, one that had considerable resources behind it and took its promotional role far more seriously. Eugenics was promoted by wealthy elites because it placed the blame for social problems on the defective biology of individuals and groups (especially non-Aryans and non-Anglo-Saxons), rather than on the economic and social system of the robber-baron era.

Eugenics arose and flourished in a context of considerable economic, political and social turbulence, the age dominated in one historian’s term, by “the search for order.”20 It was the period of massive urbanization, industrialization, increasingly unstable economic processes including “depressions” every 10-15 years, armed conflict between labor and capital, and massive unemployment. This was also the era of the Bolshevik Revolution in Russia, militant IWW (Industrial Workers of the World) agitation in the mining and lumber industries in the U.S. Pacific Northwest, the anti-immigrant hysteria of the Sacco-Vanzetti case (in which two Italian radicals in Massachusetts were accused of murder in 1921, sentenced to death and executed) and the Seattle General Strike of 1919. Eugenicists argued that their approach was the most efficient way to solve such recurrent problems and bring order into the chaotic economic and social arena. The logic of eugenics was compelling. If the increasing number and extent of social problems was largely due to an increasing number of genetically defective people in American society, then the most efficient and lasting way to solve the problem was to attack it at the source: that is, prevent the reproduction of the defectives themselves. And, of course, those deemed defective were usually the poor, ethnic minorities, the very people least able to defend themselves. Author Allan Chase put it succinctly when he stated that the eugenicists’ policies were “aimed directly at the gonads of the poor.”[21] But national efficiency was a major issue in the 1920’s and 1930’s, not only in the U.S. but in Europe as well — and in this country, efficiency and eugenics were incorporated particularly well into the ideology of the progressive era.

Efficiency brought about by the use of technically trained experts, was an effective argument in a period when inflation was rampant and, after the Depression, joblessness was high. Historian Diane Paul has pointed out that biologists and others who were opposed to, or at least skeptical about, compulsory sterilization before 1929, were considerably more open to the idea after the stock market crash of that year.[22] Eugenicists and their supporters played on concerns about livelihood, taxes, safety and social chaos to build support for supposedly scientific solutions to social problems.

Conclusion: Lessons for Today

The revelations of the Holocaust showed the extent to which eugenic logic could lead. In the wake of the Nuremberg Trials the term and concept behind eugenics certainly acquired a highly negative connotation. Still today, nothing raises more fears about new genetic claims (from cloning to genetic engineering) than to label these, in Troy Duster’s eminently useful term, a “backdoor to eugenics.” It’s unlikely that we will have a “eugenics” movement today that has the same characteristics of the old, including state-enforced sterilization laws. But there are many outcomes, deriving from different economic and social mechanisms, which might well serve the same ends. If what mattered for historical eugenic arguments was their appeal to efficiency, then treating conditions such as restlessness among school children with Ritalin, rather than improving teacher-student ratios, restoring after-school programs, providing healthy diets, and improving the overall school environment, may seem preferable to local governments and their tax bases. In view of the “bottom-line” mentality, the powerful financial interests in biotechnology, promoted by the pharmaceutical industry, genetic determinism gain a very strong set of advocates. No set of forces in an advanced capitalist society has more influence than have strong political interests combined with a profit motive.

The health-care industry is no less prone to promoting genetic determinism, especially with regard to insurance coverage. Right now, 47 states have passed some form of legislation limiting the prospects of genetic discrimination by insurance companies, but there is much leeway in how the legislation is written and interpreted. Most of the conditions that would have to be covered are clinically-diagnosed genetic diseases. But what about more vague behavioral traits, such as criminality or homosexuality? How will they come to be treated if they are seen to be the product of one’s genes?

In the 1990’s, public furor arose from a NIMH (National Institutes of Mental Health) umbrella proposal known as the “Violence Initiative,” which was aimed at exploring the genetic and physiological bases for violence in inner-city youth by studying the behavior of male macaque monkey.[23] Another program, administered at Columbia University’s College of Physicians and Surgeons, studied numerous biological characteristics of children, between the ages of six months and six-to-eight-years, who had siblings held in the New York Adolescent Detention Center. One of the aims of that study was to identify early children with criminal tendencies and intervene at some point (with boot-camp training and other highly coercive programs) before they had a chance to act out their violent drives. All of these programs fell under the rubric of mental health, using what were claimed to be the newest tools of modern bio-medicine to attack the problems of crime and violent behavior at what were claimed to be their roots — bad genes.

One thing we can learn from the past is not to make the same mistakes as our predecessors made. Geneticists in the early twentieth century failed to speak out soon enough on the misuse of their science. Most could not have known that eugenics could have such deadly results, but we are able to build on their experience. We need to be vigilant and act to contradict exaggerated claims about what genes can do because the forces that promote those claims are ever-ready to use deterministic ideas to serve their own economic and social agendas.

Garland E. Allen is an historian of science who teaches biology and the history of science at Washington University in St. Louis. He has written on the history of genetics and its relation to embryology and evolution in the twentieth century, including a biography of Thomas Hunt Morgan. He has also written on the history of eugenics between 1900 and 1950. His interests lie in relating the history of science to current controversies, including human behavior genetics claims and intelligent design.

 

References

1. Davenport, Charles B. 1910. Eugenics. New York: Henry Holt
2. Letter To W.P. Draper, 3/23/23; CBD Papers, American Philosophical Society.
3. Allen, Garland E. 1986. "The Eugenics Record Office at Cold Spring Harbor, 1910-1940: An Essay in Institutional History," Osiris (Second Series) 2: 225-264.
4. Hassencahl, Frances. 1970. Harry H. Laughlin, 'Expert eugenics Agent' for the House Committee on Immigration and Naturalization, 1921-1931 Cleveland, Case Western Reserve University, Ph.D. Thesis.
5.Selden, Steven. 1999. Inheriting Shame: The Story of Eugenics and Racism in America (New York, Columbia University Teachers College Press)
6. Coolidge, Calvin. 1921. "Whose Country Is This" Good Housekeeping 72 (February), 13-14; 106 and 109, 13-14
7. Ludmerer, Kenneth. 1972. Genetics and American Society: A Historical Appraisal. Baltimore: Johns Hopkins University Press.
8. Robitshcer, Jonas. 1973. Eugenic Sterilization. Springfield, IL, Charles C. Thomas: 31
9. Zenderland, Leila. 1998. Measuring Minds. Henry Herbert Goddard and the Origins of American Intelligence Testing. Cambridge: Cambridge University Press: 312-315
10. Morgan, Thomas Hunt. 1925. Evolution and Genetics, Princeton: Princeton University Press: 201-202
11. Davenport, Charles B, 1911 Heredity in Relation to Eugenics. New York: Henry Holt.
12. Chase, Allan. 1977. The Legacy of Malthus. New York: Alfred A. Knopf: 201-225
13. Supra 10: 204
14. Pearl, Raymond. 1927. "The Biology of Superiority." American Mercury 1: 257-266.
15. Barkan, Eleazar. 1992. The Retreat of Scientific Racism. Changing Concepts of Race in Britain and the United States Between the World Wars. Cambridge: Cambridge University Press.
16. Muller, Herman J. 1933. "The Dominance of Economics over Eugenics." Scientific Monthly 37: 40-47.
17. Riddle, Oscar. 1928. "The Control Of Heredity." Proceedings of the Third Race Betterment Conference: 62-71.
18. Jennings, 1924, “Heredity and environment,” The Scientific Monthly 19: 232-233
19. Myerson, Abraham et al., Eugenical Sterilization: A Reorientation of the Problem, New York: Macmillan Company, 1936: 71.
20. Wiebe, Robert. The Search for Order, 1877-1920. New York: Hill and Wang.
21. Supra 12: 134.
22. Paul, Diane. 1995. Controlling Human Heredity: 1865 to the Present. Atlantic Highlands, N.J.: Humanities Press International: 134.
23. Allen, Garland E. 1999. "Genetics, Eugenics and the Medicalization of Social Behavior: Lessons from the Past." Endeavour 23 (No. 1): 10-19.