Did the t-4 program have any lasting, intended, effects on the German population?

Although popular culture and collective memory have closely associated the Nazis with policies intended to change the genetic fabric of German society, the actual realities of eugenic policy within the Third Reich was far more complex. The Third Reich's eugenics program often intertwined various social prejudices and precepts with specific types of eugenics of that era. The results of this process were quite murderous, but also nugatory for the gene pool.

Eugenics itself was a very heterogeneous movement and encompassed a wide range of thinkers, scientists, and activists. One of the problem this movement, or, more properly, movements, had in the 1920s was that much of the data was proving that human heredity was far more complicated than prior generations of scientists had realized. The Hardy–Weinberg principle had already shown that the numbers needed fundamentally change a genetic population were quite vast and far larger than prior generations of eugenicists had appreciated. Studies of other diseases and conditions also revealed that heritablity and other genetic factors worked in complex ways rather than simple transmission between two generations. Some eugenics advocates modified their tenets and positions in light of this evidence. Paul Weindling's research into Weimar eugenics has shown that by 1930 a good many German eugenicists were walking away from negative eugenics, which could encompass the sterilization or murder of undesirables, and embraced more positive eugenics such as encouraging natalist policies and healthier babies among the fit. But despite the new skepticism and qualifications surrounding eugenics, there still was a popular conception of inheritable disorders and social misbehavior that often flew in the face of current research. Such sentiments had a good many advocates among the lay population and a number of politicians throughout the West. And there were of course radical professionals within eugencism who envisioned a more dramatic restructuring of the gene pool through a combination of negative and positive eugenics.

The Third Reich built on these manifestations of eugenics inside Germany and twisted them in ways that suited the leaderships' own ideological precepts. Not surprisingly, the actual working knowledge of the scientific aspects of genetics by men like Himmler or Hitler was quite limited. And this lack of realistic knowledge about genetics does show in the Third Reich's various eugenics policies. The legislation that empowered genetic health courts and the legalization of sterilization targeted vague diseases and conditions that were not fully hereditary. The sterilization laws could not legally apply to recessive carriers of disorders and doctors who sterilized healthy Germans on these grounds were subject to German criminal law. Although racial hygiene became a mandatory part of German medical education and various eugenicists found themselves the beneficiaries of state largess and patronage, the major eugenics initiatives were often patchwork and never possessed a coherent strategy behind them. The initial impetus for the euthanasia program did not emanate from above, but from below. A Saxon father in late 1938 had petitioned Hitler for permission to kill his son on the grounds that the child's deformities were too much of a burden on the family to bear. This petition helped kickstart the whole process of euthanising adults and children institutionalized in German hospitals.

Negative eugenics was only one aspect undergirding the T4 program. Many of the individuals murdered in the T4 program were likely not to breed, so even if human genetics hewed towards a simple Mendelian pattern, it would not have had a larger impact on the gene pool. As institutionalized people, they were in a controlled environment and even if their ailments were fully hereditary, they were not going to have children in appreciable numbers. To an extent, the semi-public justifications for euthanasia in state propaganda and medical journals acknowledged this fact. Although maintaining a healthy gene pool was one rationalization given, the idea of removing "worthless eaters" and other drains on society enjoyed far more prominence in the state's arguments in favor of mass murder. Internal memoranda and studies of the problem often examined the amount of resources devoted to the care of these individuals. Media justifying eugenics often foregrounded the social burden of caring for these deficient people and kept the scientific discussion of inherited problems it to a minimum. The 1941 film Ich klage an, based on an earlier 1935 novel, presented the euthanasia of the protagonist's wife suffering from MS as a moral duty to end her suffering. Other media emphasized the humaneness of putting these Germans out of their misery, while some indulged in a base and crude logic that these people were a burden Germany should not bear. Such media, like this propaganda sheet emphasized not only the grotesque nature of these individuals, but also the material costs of bearing the burden. The latter was likely Hitler's thought on the whole matter. With war clouds looming, Hitler told the Reichsgesundheitsführer Leonardo Conti in July 1939 that it would be better to free up hospital bed space and medical resources if such people were put down. In this sense, the petition by the Saxon father to murder his son came at the right time and place to get the process of of eliminating these individuals started.

As murderous as the T4 and its various satellite programs were, they did not impact the gene pool of the wider German population. Nor was that the programs' primary intent. The state's main goal had less to do with creating a healthy genetic populations but rather to remove "useless mouths" from Germany during the war. Much of Nazi discourse assumed that healthy genetics would fall into place once National Socialism had achieved a total victory. Nazi eugenics efforts never reached deeper than the expression of certain genetic traits, not their root cause, and many knew at the time that this was not scientifically-sound. Michael Straight's May 1941 New Republic expose of Nazi eugenics, "Germany Executes Her ‘Unfit,’ " accurately summed up the rationale behind Germany's euthanasia program:

[They] were not killed for mercy. They were killed because they could no longer manufacture guns in return for the food they consumed; because beds in the German hospitals were needed for wounded soldiers; because their death was the ultimate logic of the national socialist doctrine of promoting racial superiority and the survival of the physically fit.

The evolving understanding of genetics and heredity bears Straight's dismissal of Nazi eugenics out. The abortion of thalassemia-b embryos on Cypress uses a far more rigorous screening process than those of the 1930s and 40s and while this has cut into the expression of this condition, it has not changed the gene pool to prevent it occurring in the first place. As expansive and brutal as the Nazi eugenics program was, to truly impact the gene pool, the state would have had to greatly expand both the scale and timeframe of its eugenics programs on a level that would have been daunting. Tolley and Yoken's 2010 study on German schizophrenia concluded that the results of the Third Reich's sterilization and murder was that aside from a small postwar dip explained by the murder of diagnosed schizophrenics, German schizophrenia rates remained normal compared to its neighbors and in some cases, higher.

In the end, the only real material legacy of Nazi eugenics was the people it killed. It solved no health problems and did not change the larger gene pool. The Third Reich's scientific methodology was questionable even by the standards of the day and science was often a cloak for the darker impulses to remove people who do not fit into an ideal mold. It was just plain murder.