last update: June 2022
Contact: Marius Bartmann

Authors

Dictionaries commonly define the word "enhancement" as an increase or improvement in quality, value, desirability or attractiveness. In a bioethical context, the debate on enhancement in the general sense focuses on how the use of means and methods for the improvement of different human characteristics are to be evaluated morally and legally. However, the term "enhancement" in the narrower sense is only used to describe those improvements of human characteristics that cannot be understood as contributing to the restoration or maintenance of physical or mental health. According to this interpretation, enhancement measures therefore serve neither therapeutic nor preventive purposes and thus fall outside the genuine scope of medicine.

It is not always possible to draw a clear line between therapeutic measures and enhancement – enhancement measures do not fall outside the classical field of medicine simply because they are non-therapeutic improvements of healthy people. Typical preventive measures such as vaccinations are also aimed at healthy people and try to improve them by reducing their susceptibility to certain diseases. However, the field of enhancement can be distinguished from the fields of prevention and therapy, which undoubtedly belong to medicine, on the grounds that the latter, unlike the former, are related to disease. According to this interpretation, the improvements sought by medicine always serve to combat generally recognized deficiencies such as diseases or disabilities, whereas enhancement aims at the "mere" optimization of human characteristics.

Therapeutic, preventive or enhancement interventions raise ethical questions. The normative relevance already exists in the distinction between therapeutic and preventive interventions on the one hand and enhancement measures on the other. This is usually justified by the fact that health, in the sense of absence of illness and disability, is a fundamental good in which the individual and society are equally interested. In the case of enhancement, however, it must be discussed which types of improvements that go beyond therapeutic purposes might also be of interest to society. Critics of the distinction between medical interventions on the one hand and enhancement measures on the other point out that this distinction is as fuzzy as the concept of disease itself. In fact, medicine still has no generally accepted view of how to distinguish between pathological and healthy states. The enhancement debate pursues various strategies to overcome the theoretical challenge arising from the controversy about the concept of disease. As a general guideline, it is certainly plausible to identify medically indicated measures as particularly worthy of support. However, if this support is justified by a cost-benefit ratio, the benefit of enhancement measures for society as a whole does not necessarily have to lag behind therapeutic interventions.

If enhancement in the sense of the narrower definition is primarily understood as misuse (or even abuse) of biomedical means and procedures to optimize the attributes of healthy people, a further distinction can be made with regard to the methods used between pharmaceutical, surgical or biotechnical enhancement, with the latter including genetic and neurotechnological interventions. If, on the other hand, the discussion of the concept of enhancement is guided by the more general question of the normative limits within which the human pursuit of optimization should take place, there is no reason to limit the consideration to medical-technical improvement strategies. According to this understanding, educational and training programs, adherence to favorable sleeping and eating habits or the intake of stimulants such as coffee, tea or alcohol (so-called lifestyle drugs) can also be regarded as enhancement.

A further classification of enhancement measures can be made in terms of the qualities or functions that they aim to improve. With regard to the objective functions, one can distinguish between enhancement 

1. of physical performance, such as doping in sports,
2. of external appearance, such as in aesthetic medicine,
3. of cognitive abilities or emotional states as well as
4. by genetic methods.

While the improvement of cognitive abilities (3.) is often referred to in popular media as "brain doping", the term "neuroenhancement" has gained acceptance in the bioethical debate on the subject. Enhancement using genetic engineering methods (4.) can theoretically target the first three functions mentioned above. Should the human genome one day be completely understood and a reliable conclusion from a genotype to a phenotype be possible, both external attributes and tendencies for mental qualities could be changed or determined by genetic intervention.

Not all enhancement objectives can be satisfactorily covered by the four categories mentioned. One specific area, for example, concerns efforts to slow down or stop human aging. Anti-aging measures target functions from all of the aforementioned areas, because the aim is not only to grow older in good health, but also to look good and remain mentally fit for longer. Another special case is that of moral enhancement, which refers to attempts at improving the moral behaviour of people. Moral enhancement is a special case of neuroenhancement. Ethicists assume that all abilities and attributes affected by changes that cause people to act morally better are of a cognitive or psychological nature. However, it should be noted that moral enhancement is not a sub-area of neuroenhancement in the same sense as cognitive enhancement or emotional enhancement. Rather, the different theories of moral enhancement differ precisely in that some see possibilities for improving human beings more in the cognitive realm, while others see possibilities in the emotional-motivational realm. Not only the choice of methods, but also the choice of objectives and reasons why a person chooses enhancement, as well as the associated consequences for the individual and society, require an ethical assessment.

Since enhancement is an umbrella term for wish-fulfilling interventions of various kinds, the most important areas of enhancement are presented here. These will serve as concrete examples to illustrate the discourse. In this section (II.), key terms and methods are first explained for each area and then legal aspects are outlined. The next section (III.) then discusses the ethical questions and problems associated with the relevant area. The four areas are:

1. Doping in recreational and competitive sports
2. Aesthetic medicine
3. Neuroenhancement
4. Genetic enhancement 

1. Doping in recreational and competitive sports

1.1 Concepts and methods

Doping is probably the best known and oldest form of enhancement. Various sources indicate that even athletes in ancient Greece and Rome resorted to unusual diets and substances (such as mushrooms or bull testicles) to increase their physical performance. The development of medicine and technology means that doping in sports is now an ever-present and much discussed topic. The main goals of doping in sports are to increase physical strength and endurance. On a physiological level, these goals can be achieved primarily by influencing the skeletal muscles (muscle growth, composition and regeneration) and the energy supply (among other things, by improving the oxygen supply). Because athletic performance is determined not only by the physical parameters but also by the athlete's mental condition, some doping methods aimed at increasing alertness and concentration can also be classified as neuroenhancement.

Currently, Article 2.1 of the World Anti-Doping Code by the World Anti-Doping Agency (WADA) states that the "Presence of a Prohibited Substance or its Metabolites or Markers in an Athlete's Sample" constitutes a violation of anti-doping regulations. As it is difficult to provide a clear general definition of doping, the recent focus has been on the inclusion of certain substances suitable for doping in prohibited lists. Methods and practices such as Gene doping are also included. The most important list of this type is published by WADA and updated annually. The Prohibited List supplements and substantiates the World Anti-Doping Code. However, the preliminary remarks of the Code only define the meaning of these rules in very general terms: It was about protecting what was "intrinsically valuable" about sport, namely the preservation of the "spirit of sport". According to Article 4.3, substances or methods that meet two of three of the following criteria should be included in the Prohibited List: (1) scientifically or empirically proven potential of performance enhancement; (2) medically or empirically proven potential of health hazard; (3) the use of the substance or method violates said spirit of sport.

Critics of the efforts being made today in the international fight against doping have repeatedly stressed that only a fraction of the users of prohibited substances and practices could be detected through the tests currently used in competitive sports. However, the alternative approach to estimating the prevalence of doping in competitive sports by means of surveys of athletes also has its own methodological difficulties. In particular, participants in such surveys must be reassured that they will not be adversely affected by being truthful about their own use of doping substances or methods. The anonymity of survey results can be demonstrated particularly convincingly with the so-called randomized response technique which is specifically designed to provide honest information about socially undesirable behavior. Several studies have investigated the prevalence of doping among German athletes with this technique. The study results vary considerably depending on the specific survey design and the athlete cohorts involved; however, they consistently support the hypothesis that the proportion of athletes who resort to the use of doping substances is many times higher than the results of doping tests suggest. According to a number of studies, at least in some types of sports, the use of performance-enhancing substances and methods in recreational sports is even more widespread than in competitive sports.

1.2 Legal aspects

Doping as such, i.e. the consumption or use of substances or methods that are prohibited in professional sports, was not illegal in Germany for a long time. However, doping offences were subject to the jurisdiction of the sports courts. The sports courts, which were established by the various sports federations, were able to impose sanctions on athletes who violated the anti-doping rules laid down in their respective statutes.

This legal situation changed in 2015 when the German Bundestag approved the coalition's draft for an Act against doping in sport (AntiDopG) which was slightly amended in 2017 and 2020 and for which further amendments were discussed in April 2021. The law prohibits the use of a doping agent or a doping method as defined in the International Convention against Doping in Sport without medical indication "with the intention of gaining an advantage in a competition of organized sport". The penalties provided for this offense of "self-doping" are imprisonment of up to three years or a fine. The production, sale or trade, procurement and prescription is also prohibited by the Anti-Doping Act under Section 2. In particularly serious cases, such as health hazards, bodily injury, death or distribution with a high degree of personal gain and major financial advantages, a prison sentence of up to ten years may be imposed. Before the Anti-Doping Act came into force, the possession of large quantities of doping substances, their placing on the market and their use by others was already classified as a criminal offense in the Medicinal Products Act (AMG). Several other European countries, such as France, Italy or Spain, have similar prohibitions under criminal law on the handling of doping substances or methods.

As the present draft of the Anti-Doping Act prohibits self-doping only in the context of competitions in organized sports, the relevant rules essentially refer to top athletes who are subject to the control regime of the National Anti Doping Agency Germany (NADA). Accordingly, the use of doping substances and methods in recreational sports will continue to be legal, at least as long as the use of the substances in question is not prohibited for other reasons, for example because it is in conflict with regulations of the Medicinal Products Act (AMG) or the Narcotics Act (BtMG). Decisive for this is the constitutionally protected right of personality, which includes a right to endanger oneself if others are not harmed as a result. Nonetheless, anyone who provides someone else with access to substances or methods that are prohibited in top-level sports so that they can use them for performance enhancement purposes is acting illegally under both old and new legislation. Here it is irrelevant whether the person concerned intends to create an advantage for themselves in a competitive sporting situation by using the means in question or not. For example, both the personal trainer who passes on anabolic steroids (which he has illegally procured himself) to a hobby bodybuilder for the purpose of building up muscles, as well as the doctor who makes this possible by prescribing a corresponding substance (which would be legal except for the purpose) are liable to prosecution. 

2. Aesthetic medicine

2.1 Concepts and methods

Aesthetic medicine is another established field of wish-fulfilling medicine. In contrast to doping, however, this form of enhancement is largely accepted by society and in some cases is already considered a routine medical procedure, especially with regard to surgical measures, which will be discussed below.

According to the German Society of Plastic, Reconstructive and Aesthetic Surgeons (DGPRÄC), procedures are described as aesthetic if their aim is the "harmonization of the external appearance" and they are performed without medical necessity but due to "dissatisfaction" with the appearance and can improve the patient's body image. This could help to alleviate any lack of self-confidence, feelings of inferiority, depressive moods and psychological difficulties in coping with everyday life. According to the German Medical Association’s journal Ärzteblatt, the most frequent aesthetic procedures, apart from the correction of ears, breast corrections and rhinoplasties, are upper eyelid lifts, liposuction and breast enlargement. There is no central German register for cosmetic surgery. 

Further distinctions in terms of benefits, risks and objectives may be relevant for an ethical assessment. For example, a distinction can be made between interventions that reduce negative attention or stigmatization and those that aim to increase positive attention in the form of a mere increase in attractiveness. Under certain conditions, for example, it would be acceptable to protect children from stigmatization by means of aesthetic surgery. On the other hand, operations with the sole aim of increasing physical attractiveness in minors should be avoided.

2.2 Legal aspects

The terms "cosmetic surgery" or "aesthetic surgery", which are quite common in general usage, are not legally protected. The mere description of a doctor as a "cosmetic surgeon" or the offer of cosmetic surgery does not say anything about the actual qualifications held. In Germany, only the title "Facharzt für Plastische und Ästhetische Chirurgie" (specialist physician for plastic and aesthetic surgery), which is used in the context of continuing medical training law, is protected and must be obtained with an additional training qualification in "plastic surgery". When doctors without such a specialization offer aesthetic operations, the quality of their execution, for instance in the case of a dispute about a possible treatment error, is nevertheless measured by the standards of specialist doctors. In 2005 the specialist physician title "Facharzt für Plastische Chirurgie" (specialist physician for plastic surgery) was extended to include the field of aesthetic surgery. This can be regarded as an official recognition of the enhancement part of the medical service spectrum, because aesthetic surgery, in contrast to plastic or reconstructive surgery, is characterized precisely by the absence of a medical indication.

With regard to non-therapeutically indicated aesthetic surgery for minors, it is currently not yet clear whether and when legal restrictions or a ban will be passed in Germany. In contrast, in Austria, for example, in 2013 the Federal law on the performance of aesthetic treatments and operations (ÄsthOpG) came into force, which prohibits cosmetic surgery on children under the age of 16 and provides for psychological counseling for 16 to 18-year-olds.

Overall, however, the lack of a medical indication for aesthetic surgery results in a number of peculiarities for the doctor-patient relationship, some of which also have legal relevance. For example, particularly high demands must be placed on the information and clarification obligations arising from the treatment contract between doctor and patient. As a general rule, the less urgent and the more dangerous an intervention is, the more carefully must information be provided before a medical intervention. As purely aesthetic procedures are not medically necessary, doctors must provide particularly comprehensive and detailed information about the likelihood of success, treatment alternatives and the risks of health and financial damage. The special duties of care of doctors who offer aesthetic procedures also include checking whether the desire for such a procedure is rooted in a mental disorder requiring treatment. For example, aesthetic interventions are considered to be contraindicated in cases of body dysmorphic disorder. Patients affected by this body perception disorder perceive minor blemishes as serious deformations. Surgical correction of these flaws leads at best to a temporary improvement in the self-esteem of these patients, but often the dissatisfaction shifts directly to a new feature. If the body dysmorphic disorder remains undetected, sufferers occasionally undergo a whole series of aesthetic procedures. Special requirements also apply to advertising for aesthetic surgery: For example, according to Section 11 of the Law on Advertising in the Health Care System (HWG), advertising with before and after pictures is prohibited.

3. Neuroenhancement

3.1 Concepts and methods

The improvement of cognitive abilities by means of pharmaceuticals or other technical methods actually developed for medical treatment is a field of enhancement that is still little researched. The current debate on the use of medical or technical means and procedures by healthy people to optimize mental qualities is therefore based on the non-therapeutic use of psychotropic drugs, which is becoming more and more prevalent due to increasing performance pressure and easier availability. The older designation of the field of investigation as "cosmetic psychopharmacology" refers on the one hand to presumed opportunities to improve mental well-being, which could for instance be offered by modern antidepressants with a favorable side effect profile. On the other hand, the focus has increasingly shifted to attempts by healthy people to positively influence cognitive abilities such as concentration or memory by taking psychostimulants, for example to better meet increasing academic and or professional demands. The term "cognitive enhancement" has become established as a separate term for improvement efforts in the cognitive area. In recent years, the term "neuroenhancement" has become established in the academic field as a broadly defined generic term that refers not only to cognitive abilities but also to emotional and motivational optimization goals and, in addition to pharmaceutical preparations, also includes neural or genetic engineering procedures. In media and press reports, the phenomenon is also referred to – usually in a derogatory manner – as "brain doping".

Depending on the psychological target function, preparations from different pharmacological substance classes are claimed to also achieve specific improvements in healthy people. For the purposes of cognitive enhancement, psychostimulants are the first choice. These include a wide variety of substances whose preparations are in some cases freely available (caffeine), but mostly on prescription (modafinil, atomoxetine) and in many cases are even subject to the Narcotics Act (BtMG). One should not be misled by the fact that many psychostimulants are legally considered narcotics, although they are typically not narcotic but rather stimulant. The German Narcotics Act classifies some stimulants as trafficable (most amphetamine derivatives such as methylphenidate) and others as non-trafficable narcotics (MDMA, cathinone). In addition to stimulants, theoretical considerations have resulted in drugs from the anti-dementia class (e.g. Alzheimer's drugs with the active ingredient donepezil) being attributed a benefit for cognitive enhancement purposes, such as improved concentration and cognitive ability. The use of stimulants can have positive effects not only in the cognitive area but also in emotional and motivational areas. Anxiolytics and antidepressants are discussed as neuroenhancement drugs primarily due to their potentially positive effect on the well-being and mood of psychologically healthy people.

In addition to pharmaceutical preparations, neurotechnological procedures for stimulating the brain can also be considered for neuroenhancement purposes. However, all procedures whose application requires neurosurgical intervention on the brain, such as Deep brain stimulation, entail associated risks that are too serious for their use to be acceptable for neuroenhancement in healthy individuals. In contrast, other neurostimulation methods, which are non-invasive in this sense, appear to be safe enough to be used without a therapeutic indication, which is something that is regularly done in neuroscientific research. While non-invasive stimulation methods such as Transcranial Magnetic Stimulation (TMS) are unlikely to be widely used as enhancement methods due to their high technical complexity, methods such as Transcranial Direct Current Stimulation (tDCS) are affordable for almost everyone and technically easy to master. Neuropsychological experiments have provided initial evidence of modest enhancement effects of non-invasive stimulation procedures, particularly in the cognitive area. However, it is largely unclear whether such effects translate into relevant benefits in everyday working and learning situations.

3.2 Legal aspects

The constitutionally protected right of personality, which includes the right to endanger oneself, means that the use of neuroenhancement preparations is generally not a criminal offense. However, the possession or acquisition of the respective preparations may well be illegal, with significant legal differentiations resulting from the type of substance consumed. Many prescription drugs, but also drugs from the black market, that are consumed for neuroenhancement purposes, contain substances that are subject to the regulations of the German Narcotics Act (BtMG). In addition to the production of or trade in narcotics, the BtMG prohibits both their possession and their purchase, even if this is only for personal consumption. Impunity for the use of narcotics can only be invoked if they are given for immediate use under supervision (so that they do not become the user’s own property). As this is a rare constellation in the use of neuroenhancement substances, the procurement of narcotics without a prescription for the purpose of enhancement is usually a criminal offense. For example, if a young person has received a methylphenidate-containing drug on a narcotic prescription for the treatment of his ADHD, but passes the tablets on to a friend who wants to take them to improve his cognitive performance, both of them are in violation of the BtMG. Furthermore, Section 6a of the Medicinal Products Act (AMG) prohibits the possession of substantial quantities of certain substances if they are to be used for doping in sports. The annex to the AMG, which lists the substances concerned, is based on the Prohibited List of the World Anti-Doping Agency (WADA).

Anyone who attempts to obtain a prescription for a narcotic for themselves or others through false information from a doctor is also liable to prosecution under the Narcotics Act (BtMG, Section 29 (1), no. 9). Even the doctor who falls for such a deception is in many cases acting illegally, for example when issuing a prescription, if he neglects the special duties of care required when prescribing narcotics. Obtaining a prescription by deceiving a doctor can be a violation of the law even if the desired neuroenhancement preparation is not a narcotic but a drug subject to normal prescription requirements. Anyone who is reimbursed in whole or in part by their health insurance company for the cost of a fraudulent prescription is guilty of fraud.

4. Genetic enhancement

4.1. Concepts and methods

The debate on interventions in the human genome for non-medical purposes can be regarded as a promising and currently much-discussed area of enhancement. Although genetic enhancement is not yet very widespread compared to other areas, the rapid development of new methods allows scenarios in which changes in the genetic material go beyond the treatment of diseases.

The specific modification of genetically determined traits according to individual wishes is called "genetic enhancement" or "enhancement genetic engineering". In general, a distinction is made between somatic cell genetic engineering, with which the genetic material of somatic cells is specifically manipulated in order to change a certain trait in an individual, and germ cell genetic engineering, with which desired traits of offspring can be influenced at will via the germline.

First attempts to treat diseases with the help of gene therapies began in 1990, when the world's first gene therapy treatment was carried out on the then four-year-old Ashanti DeSilva, who suffered from a rare severe immune deficiency. Gene therapy measures were at first often accompanied by severe setbacks. The first approved drugs were soon withdrawn from the market due to limited success (Cerepro, Glybera) and the initial euphoria about new gene therapy methods quickly died down, particularly due to the problematic medical risk-benefit ratio. However, new advances and developments have now brought gene therapies back into focus as potential therapeutic methods. 

All gene therapies that have been developed and tested in clinical trials to date have aimed to treat serious diseases using somatic cell genetic engineering. The most comprehensively researched form of gene therapy in the field of somatic cell genetic engineering to date is the addition of genes to replace missing or defective genes. This is done with viral and non-viral methods. 

The viral method exploits the ability of viruses to introduce genetic material into cells. For this purpose, the viruses are genetically modified in such a way that they no longer possess any pathogenic, i.e. disease-causing, properties and therefore only carry the correct gene into the cell. These so-called "viral vectors" are either inserted directly into the desired tissue or into those stem cells that are cultivated outside the body and transplanted at a later stage. This method then allows the correct gene to be read in the cells. A promising gene therapy with viral vectors is for example the ex-vivo stem cell gene therapy Strimvelis. It is directed against a rare immunodeficiency caused by adenosine deaminase deficiency (ADA deficiency): Infusion of CD34+- bone marrow cells transformed with an ADA-containing vector significantly increased the number of active immune cells in children suffering from a rare severe immunodeficiency (ADA-SCID). The survival rate so far is 100 %. 

Non-viral gene therapy methods include the introduction of DNA into the cells by injection, electroporation (temporary increase in the permeability of cell membranes), gene gun (transport by firing particles), sonoporation (acoustic space formation by microbubbles), magnetofection (use of magnetic fields to transport nucleic acid-containing particles into the cells in concentrated form) and the use of oligonucleotides, lipoplexes, dendrimers and inorganic nanoparticles. The disadvantage in all these cases is that the gene cannot be transported precisely into the genetic material of the cell. This may result in insertional mutagenesis, because the gene first has to find a new random place in the genome and may influence other important genes as a result.

Another non-viral approach to gene therapy is the correction of defective genes with the help of nucleases. Techniques known as "gene scissors" such as CRISPR/Cas9, TALEN and ZFN can also use the properties of nucleases to cut DNA precisely and sequence-specifically. These techniques are much newer than those of viral vectors, for example, and have therefore not been researched very much. Promising experiments with CRISPR/Cas9, in which DNA sequences within the cells of cell cultures and experimental animals can already be inactivated, supplemented or excised very cost-effectively and precisely using an enzyme, ultimately give rise to hopes of treating serious human diseases such as cancer or AIDS. But even here, errors or so-called "off-target effects" like point mutations, deletions, further insertions, inversions and translocations are to be expected.

The application of targeted germline interventions in embryos, germ cells or stem cells must be evaluated differently and are associated with different cost-benefit risks. In general, germ cell genetic engineering nevertheless carries significantly higher risks of unforeseeable consequences than somatic cell gene therapy and therefore faces more comprehensive technical and ethical evaluations. For this reason, no clinical trials have been approved in Europe or the USA for the time being. A first study on the use of CRISPR/Cas9 in human embryos was published in 2016. In 2018, the world's first case of two genetically modified girls being born in China aroused a great deal of international attention.

4.2 Legal aspects

There are approaches for international legal agreements on gene therapy procedures, but these have not yet been ratified by numerous countries. For example, interventions in the human genome are only permitted for preventive, diagnostic or therapeutic purposes according to Article 13 of the Council of Europe's Biomedicine Convention, which came into force in 1997. Any intervention with the aim of genetically modifying the offspring, including various interventions in the germline, is prohibited in order to protect human rights and human dignity. However, the same article presents a number of questions of definition and different interpretations. Similarly, Article 24 of the UNESCO's Declaration on the Human Genome and Human Rights, adopted in 1997, states that germ-line interventions are contrary to human dignity. However, there is no clear prohibition. Instead, the UNESCO's International Bioethics Committee (IBC) should merely carry out consultations and make recommendations. In 2015, the IBC called on the member states to adopt a common moratorium on germline interventions. Although Article 3(2) of the EU Charter of Fundamental Rights prohibits all eugenic practices, this standard may be extended and discussed in the context of therapeutic applications.

The legal situation in foreign legal systems is extremely diverse. In Germany in particular, a legal distinction is made between somatic gene therapy and germline therapy, but there are no explicit regulations or guidelines for dealing with germline interventions. While in the field of somatic gene therapy the emphasis is on reducing risks by means of a network of substantive permissibility conditions and thus enabling their use within a responsible framework, the artificial modification of the genetic information of human germ cells and the use of these through fertilization is prohibited under Section 5 of the Embryo Protection Act (ESchG). Section 2 ESchG also prohibits the use of human embryos for research purposes.

The concrete legal applications of medically indicated gene therapies in the context of clinical trials have so far been limited to regulations for drugs and research. Gene therapy medicinal products are prescription-only medicinal products and are excluded from the centralized approval process. However, there is a manufacturing permit requirement. Relevant regulations can be found in the Medicinal Products Act (AMG), the ordinance on good clinical practice (GCP Ordinance) and the Genetic Engineering Act (GenTG).

As genetic engineering is still a rather recent field of research and the human genome is far from being fully explored, genetic interventions in the human genome sometimes involve great uncertainty. Not only the benefit-risk ratio of gene therapy in general must be carefully weighed, but also that of genetic enhancement in particular. With regard to the benefit factor, genetic engineering can be used both for the treatment of diseases and for enhancement purposes. Fighting disease is generally a highly valued objective and takes precedence over correcting a specific other trait. Gene therapies and the research and development of genetic remedies can therefore be considered more desirable, even where there is an existing risk, than genetic interventions involving enhancement without medical indication. Particularly interventions in the germline still involve incalculable risks and are therefore considered ethically irresponsible by the German Ethics Council. For this reason, in its current statement from 2019, the German Ethics Council calls for an application moratorium and recommends that the Federal Government and the Bundestag work towards a binding international agreement.

Another aspect is that genetic interventions are (still) a very expensive undertaking due to the high research effort involved. Therapies have to be individually adapted and are currently still limited to small target groups, which means that the costs amount to several hundred thousand euros per patient. In the long term, germline therapies, but also somatic gene interventions, could offer cost savings compared to conventional treatments, as no follow-up treatments are necessary if the therapy is successful. Increasing experience with genetic interventions in the medical field could make this type of therapy an equal or even preferable option.

Ethical considerations for the evaluation of the areas and methods of enhancement often start with the associated, but partly still unresolved questions of health risks and side effects. However, deeper ethical considerations are often based on the assumption that the circumstances in which a person chooses enhancement are subject to certain ideal conditions: effectiveness and proven safety of the intervention and absolute voluntariness. The following examines the most widely discussed ethical arguments. Here, too, general questions of the distinction between naturalness and unnaturalness (1.) as well as unresolved questions of the safety and distinction between disease and enhancement will be addressed, especially with regard to challenges to medical ethics (2.). Subsequently, the possibility of a threat to equality (3.) as well as to personal identity and personality (4.) is discussed, which lastly also includes questions concerning autonomy and authenticity (5.).

1. Enhancement against nature?

Especially futuristic enhancement scenarios involving, for example, performance optimization through genetic interventions, such as the introduction of animal genes into the human genome or the acquisition of completely new abilities by coupling the human body with technical systems, are often met with the reservation that the interventions in question are unnatural or in any case violate human nature. "Naturalness" arguments against enhancement in general or against certain forms are fraught with two major difficulties. On the one hand, there is no consensus on how to define human nature or nature as such more precisely in conceptual terms. On the other hand, the question arises as to why humans should recognize nature as a guideline or boundary to their actions.

A common understanding of the concept of nature is determined by the opposite concept of culture: While culture refers to what has been created by humans or "artificially" changed by them, nature, according to this understanding, stands for everything that exists independently of humans or is unaffected by them. On this basis, it is possible to use various phenomena to distinguish natural from artificial or culture-related aspects. From an ethical point of view, however, the juxtaposition of nature and culture alone does not provide a plausible justification for interpreting nature as something fundamentally worth preserving. Rather, humans seem to be in an elementary conflict with nature, as they can only survive by intervening in nature. Neither are cultural products such as Bach cantatas or mathematical evidence negative "per se", nor are natural phenomena always to be assessed positively, as demonstrated by volcanic eruptions or epidemics. Consequently, against the background of this definition of the concept of nature, enhancement measures need not be regarded as problematic simply because they are unnatural in this sense.

In a second popular interpretation, the nature of a thing stands for its "essence". This interpretation is relevant when enhancement is considered incompatible with human nature. However, it seems ill-suited to validate a general suspicion of human improvement efforts, as most positions of philosophical anthropology agree that it is an important trait of humans not to be satisfied with their inadequate natural endowment, but to supplement or perfect it with technical and other cultural advances. Nevertheless, the objection that individual techniques or objectives of enhancement are contrary to human nature seems justified. For example, some of the many bioethicists who consider interventions in the human germline to be fundamentally unacceptable point out that this would permanently change human nature in terms of its gene pool. What speaks against this, however, is that even when attempting to explicate human nature through the genetic stock of the biological species Homo sapiens, the natural change in genetic make-up resulting from evolution must be taken into account. Against this background, it is not particularly plausible to regard artificial interventions in the human genome as fundamentally ethically questionable. If, on the other hand, one merely demands that only those genetic manipulations should be avoided which would create individuals who could no longer be considered members of the species Homo sapiens in the sense of the biological concept of species, this restriction would only affect the most extreme forms of genetic enhancement conceivable.

An additional problem of naturalness arguments is that they discredit the processes in question as such, and not only their applications for enhancement purposes. This can cause uncertainty or even discrimination for people who benefit from the procedures in question. For instance, if it is deemed unacceptable to enable people to control technical systems through the power of thought by developing suitable interfaces between brains and machines, this would not only apply to cyborgs with superhuman abilities, but also to people who could use such interfaces to compensate for any disabilities.

Even if one does not consider it convincing for the conceptual and normative reasons mentioned above to flatly reject enhancement procedures because of their unnaturalness or artificiality, one can still refer to the concept of nature in a weak sense. For example, in line with the slogan "nature knows best", some bioethicists argue that special caution is required whenever natural boundaries are crossed.

2. Enhancement as a challenge to medical ethics and possible addiction potential

If medicine in the traditional way is understood as a curative science, it can already be deduced from the literal meaning that doctors intervene in order to restore health, i.e. mainly in case of illness. In addition to this view, a "positive", i.e. not deficit-oriented, understanding of medicine as a science that deals with the conditions of health and the ways to promote, preserve and restore it has recently become established. This reinterpretation remains vague if health itself is only understood negatively as the absence of illness. However, there have been a number of attempts to give the concept of health a positive connotation. Particularly prominent, although admittedly not uncontroversial because of its ambitious claim, is the definition by the World Health Organization (WHO), which defines health in its 1948 constitution as "a state of complete physical, mental and social well-being and not merely the absence of disease or infirmity". If this view of health were to prevail among doctors, with the resulting definition of the field of medicine, enhancement measures should no longer appear to them to be "outside the profession", at least if such measures contribute to the promotion of well-being.

However, doctors experience enhancement measures as a challenge to their professional self-image not only because they question a traditionally disease-based view of medicine. Another concern is that the increasing importance of such measures within the range of medical services could further fuel the trend towards the commercialization of medicine, which is already perceived by many as problematic. Doctors, like currently aesthetic surgeons or sports physicians involved in doping, are worried that they will be suspected of being more interested in their own profits than in the well-being of their patients or clients. This could lead to a loss of trust and therefore erode the basis of the doctor-patient relationship. The accusation of the commercialization of medicine is sometimes combined with that of the medicalisation of modern societies, according to which medical solution strategies are increasingly sought for problems whose roots actually lie in the social sphere.

Another problem area relates to the distinction between disease and enhancement and the prescription of drugs initially indicated for therapeutic use as an enhancement for healthy individuals. This is problematic not only with regard to potential drug dependence, but also because there are no long-term studies on the use of drugs in so-called "off-label use", i.e. use outside the original purpose and approval. This gives rise to concerns that the prevalence of drug dependence could increase significantly if more and more people were to take medication to optimize certain traits without any medical reason. This worry is particularly pertinent to the field of neuroenhancement, as it involves the use of preparations which influence the central nervous system or the psyche and therefore have a fundamental potential for dependence.

Pharmaceutical preparations that regularly cause dependence can be made subject to the Narcotics Act (BtMG) in Germany. Since the right of personality includes a right to self-endangerment, the classification of substances as narcotics is not primarily concerned with protecting consumers from dependence. In order to justify legal control of the use of certain substances, reference is made to the socially harmful consequences of addictions, which in the case of common illegal drugs manifest, for example, in the form of drug-related crime, incapacity to work and also as consequential health problems. Whether the permanent and regular use of pharmaceutical preparations for enhancement purposes results in comparable disadvantages for the general public is unclear. It is noteworthy in this context that many users of neuroenhancement preparations are highly performance-oriented, whereas most drug users seem to be more interested in personal enjoyment. For example, someone who is interested in cognitive enhancement to better meet professional requirements may even (temporarily) make an increased contribution to the common good, in spite of a resulting dependence. However, due to the lack of long-term studies, the approval and implementation of which is highly problematic because of the principle of non-harm to others, it is not possible to foresee to what extent such use could also entail adverse health effects.

3. Enhancement as a threat to equality

Enhancement may pose a threat to equality not only with regard to the question of the reasonableness of the preparations and methods, but also with regard to questions of social distributive justice and the associated social pressure.

It can therefore be considered unjust in several ways if individuals gain advantages over others through the use of enhancement measures. For example, ensuring fair competition is at the heart of the fight against doping in competitive sports. The mere fear of no longer being competitive because other competitors may resort to prohibited performance-enhancing substances can be a strong motivation for the use of enhancement methods. It should be noted that athletes are under similar pressure when they know that their competitors are using authorized training facilities, materials or equipment that are not available to them (e.g. altitude training). As in the case of doping, it is also of concern when students try to improve their exam performance with illegally obtained prescription drugs, even if the use of such drugs is not explicitly prohibited in the relevant examination regulations. The reason for the concern is that it is clearly unacceptable to expect the other exam participants to also illegally acquire neuroenhancement drugs with uncertain efficacy and sometimes considerable side effects, in order to maintain an equal footing with the cognitively enhanced candidates. The associated question of the reasonableness of enhancement interventions or the consumption of neuroenhancement drugs would have to be reassessed if some of them were to be considered safe enough to be approved for use in healthy adolescents or young adults. However, even if it were permitted to take neuroenhancement drugs without a medical reason, their use would probably not be open to everyone because not everyone would be able to afford them. Therefore, even in a scenario with a legally available neuroenhancement drug with few side effects, it remains questionable whether it is unjust if wealthy individuals or groups of people gain further competitive advantages over less privileged ones by taking expensive psychotropic drugs.

With regard to the question of what type and extent of social pressure is considered acceptable, it should be noted that the answer varies greatly for different areas of competition in society. In reality, there is extremely high competitive pressure wherever very special skills and qualities are decisive in determining suitability for coveted social positions. For instance, anyone aspiring to a career as a television presenter faces high expectations regarding their external appearance. It is generally considered reasonable that applicants in this field should be able to remain competitive by investing considerable time and money in cosmetic procedures and physical training. Particularly in light of the health risks associated with such procedures, it appears problematic when applicants additionally optimize their appearance with aesthetic surgery. Even if the use of such methods is legal, it is ethically dubious when, as a consequence, others are pressured into potentially endangering their health by using such methods as well. When evaluating these and other competitive situations, it is also important to take into account the level at which the pressure to use such measures arises: at the level of the individual, society, or the state. For example, it appears particularly problematic when pressure is exerted by the legislator or institutions. Thus, it would be unacceptable coercion if a television station were to ask in job interviews whether a person might be willing to undergo certain surgical procedures.

When it comes to questions of equality with regard to the reasonableness of interventions and the use of enhancement preparations, those with a liberal attitude towards the use of enhancement measures like to counter them by pointing out that our society also finds it acceptable when parents pay for private tutoring for their children or when television presenters change their appearance through privately financed aesthetic surgery. The answer to this argument can again be that possible future inequities should not be justified by referring to currently de facto accepted inequities. Instead, concerns about the equality of socially accepted pharmaceutical enhancement or corresponding interventions should be taken as an opportunity to generally rethink the liberal approach to enhancement measures in all areas.

Concerns about the possible exacerbation of existing social inequities through the widespread use of enhancement measures arise primarily when not everyone has access to these measures. The state could therefore counter these concerns by guaranteeing free access to certain enhancements. Proponents of pharmaceutical neuroenhancement argue, for example, that subsidizing effective and safe neuroenhancement drugs in particular might be in the public interest in the future, because improved cognitive skills would help people in many positions to perform their service to society more efficiently. The answer to such musings could be that it would be a waste to use limited public funds to optimize the mental abilities of healthy people whilst optimal care for sick people is not guaranteed.

Whether the widespread use of a particular enhancement method will promote unfair social conditions is difficult to predict with certainty, given the many factors influencing the development of such conditions. However, there are already certain prohibited lists that severely restrict the unfair use of enhancement preparations. Fairness is particularly important in sports competitions, so it is not surprising that the inclusion of a product on the anti-doping organizations' Prohibited List is already legitimate when its use could potentially lead to distortion of competition. It would be more difficult to justify such preventive bans in relation to potential enhancement procedures in other areas of society that are not so consistently oriented towards egalitarian ideals. After all, every ban means a restriction of individual freedom, which is easier to legitimize in the protected competitive area of sports than in everyday competitive situations. The potential unfair consequences of new enhancement methods are not only uncertain, but must also be weighed against potential individual and social benefits. For these reasons, many bioethicists are of the opinion that aspects of fairness justify a policy of state supervision and control over the development and application of such procedures, rather than outright prohibitions.

The question of whether enhancement measures should be required in order to be able to occupy certain social positions also depends on the available alternatives. One example would be a neuroenhancement preparation with few side effects that could significantly reduce the error rate of surgeons or air traffic controllers. In other areas, too, enhancement could certainly save costs and thus reduce the burden on the health care system. If genetic enhancement was able to reduce the expression of undesirable traits such as aggressiveness or strengthen mental stability, potential follow-up costs could be prevented. With regard to the question of the acceptability of social pressure, an air traffic controller or surgeon who does not want to bow to the social expectation of minimizing their error rate by using an approved neuroenhancement drug would still be able to choose from enough other satisfying fields of activity. A highly problematic development would be conceivable, on the other hand, if the consumption of potent neuroenhancement drugs beyond specific occupations became common practice among broad sections of the population. This could lead to a dramatic increase in the demands placed on certain cognitive skills, so that non-enhanced individuals would only be given the undemanding social tasks. The possible benefits to society that might result from an increase in the average mental capacity of the population would then have to be weighed against the risk of the emergence of a two-tier society with a non-enhanced underclass.

In general, however, social pressure tells us nothing about its ethical or legal acceptability. Just as in the case of concerns about the distributive justice of social opportunities, the normative assessment of potential social pressure toward enhancement is dependent on criteria of reasonableness. Use of a particular enhancement measure appears to be all the more unreasonable the higher the associated risks are on the one hand and the financial and personal costs are on the other. Furthermore, for both problem areas, what constitutes a reasonable level of inequality or social pressure can only be determined more precisely when compared to similar social conflicts.

4. Changes in personal identity and personality

Particularly neuroenhancement is occasionally seen by critics as a threat to personal identity. Generally, this concerns the fear that the user of a particular enhancement method might change so fundamentally that the person in question could no longer be considered to be the same person they were before using the method. To avoid misunderstandings, it is useful to distinguish between a weak sense and a strong sense in which a person's identity may be affected. The weak sense describes character changes, which can also include so-called "identity crises". Accordingly, it is feared that the fundamental characteristics of a person will change more or less profoundly, which may lead to doubts about their own identity, both for themselves and for others. Even if such changes can be experienced as a crisis, the identity of a person does not usually disintegrate in the course of these changes to such an extent that one is faced with a completely new person in the end. If, on the other hand, a change is so radical that the original person seems to be replaced by a completely different person, this can be called a major change in personal identity. Not every definition of personhood leaves theoretical room for this extreme variant of a change of personal identity. If this possibility is considered, bioethical literature usually speaks of identity being affected in a numerical sense. To describe the understanding of identity, which corresponds to changes in identity in a weak sense, one speaks of an "individual" or even "narrative" identity as opposed to numerical identity, depending on the theoretical background.

The changes in personal identity anticipated by critics of enhancement are usually seen solely as a threat. This purely negative view is only appropriate when personal identity in a strong sense is at stake. However, the psychological consequences of enhancement are unlikely to ever be so dramatic that it might seem plausible to question the continued existence of the original person. It is likely that any changes that may affect individuals in the course of using enhancement procedures will only affect identity in the weak sense. From a psychological point of view, most of these mental effects may be described as personality changes. Such effects can also occur as side effects beyond neuroenhancement, for example when doping with anabolic steroids leads to increased aggressiveness in competitive athletes. Although this is an example of a personality change through enhancement, which may be undesirable in most contexts, personal identity in the weak sense can also fundamentally change for the better: For example, if someone succeeds in overcoming (non-pathological) shyness by taking a (not therapeutically indicated) antidepressant, this could be considered a positive personality change through neuroenhancement. The personality could indirectly change even more, if, for example, the person's self-esteem or self-satisfaction were to increase significantly due to reduced social inhibitions.

Both of the concepts of personal identity distinguished here can be useful for the ethics of enhancement. In conjunction with a suitably formulated concept of personhood, the concept of a major change in personal identity can serve to demarcate an area of unacceptable psychological consequences of enhancement measures. The practical relevance of this demarcation is rather low, because it involves such radical breaks in the mental continuity of persons that any intervention that would threaten the personal identity in this sense would be disqualified from being considered a possible enhancement procedure. In contrast, the weak sense of personal identity has shown to be useful when trying to make a differentiated assessment of the psychological consequences of enhancement procedures, because it allows the distinction of both particularly relevant negative and positive effects. It seems obvious to fall back on conceptual resources of psychological personality theories when describing these effects, because the concept of personality offers the possibility to distinguish only temporary and peripheral psychological effects from those which, due to their relative stability and centrality, are decisive for the individuality or weak sense of identity of a person. In addition to conceptual criteria for describing personality changes, normative criteria are also required in order to evaluate them from an ethical perspective. For example, unforeseeable personality changes may be fundamentally more problematic than those with a known likelihood of occurrence, because persons interested in enhancement can only be specifically informed about the latter.

5. Threats to autonomy and authenticity 

Occasionally, enhancement procedures meet with ethical reservations because they are seen as a threat to the self-determination or autonomy of their users. As already in the case of the concept of personal identity, it is also helpful with regard to the concept of autonomy to first draw a fundamental distinction. The concept of autonomy is used firstly to assign or deny persons the ability to self-determination in certain fundamental or "basic" respects. For example, the legal concepts of legal capacity, ability to give consent, ability to take legal action or even religious majority denote field-specific aspects of autonomy which people either have entirely or not at all at any given time. In order to be considered autonomous in the respective regard, persons must have different abilities in a form that meets certain minimum criteria, such as the ability to understand relevant contexts. Individual differences in these abilities that go beyond this do not play a role in the attribution of the respective self-determination ability. The application of the concept of autonomy follows a different logical structure if it is based on an ideal understanding of self-determination: Theories of ideal autonomy make it possible to evaluate courses of action, personality traits or even entire life or self-concepts as more or less self-determined, depending on how well they can be aligned with a certain ideal of self-determination.

Enhancements are primarily considered a threat to the ideal concept of self-determination. The loss of autonomy in a fundamental sense may at best be accepted as a serious side effect in desperate therapeutic decisions, but would be completely unacceptable as a consequence of an enhancement procedure. Autonomy-related concerns about enhancement should therefore generally not be understood as meaning that its users literally lose their free will since they no longer meet certain minimum requirements for autonomy. Rather, there is a fear of a gradual decline in individual skills that are relevant to self-determination in its various aspects. In this sense, concerns that enhancement procedures could lead to dependence, for example, call into question the autonomy of users, because addiction and dependence mean a partial loss of the capacity for self-control. The argument familiar from the discussion on aesthetic enhancement, namely that the clients of aesthetic surgeons are not really free in their decisions, but are externally influenced by social expectations and unrealistic beauty ideals, also refers to an ideal understanding of autonomy. Ultimately, it can be questioned whether any decision in the sense suggested here can ever be regarded as autonomous, insofar as every single one of our consumer decisions appears to be at least partially influenced by advertising and the media.

A more precise assessment of concerns about the autonomy of users of enhancement requires a more detailed analysis of the respective invested understanding of ideal self-determination. A common definition of ideal autonomy is associated with the concept of authenticity. In the first instance, authenticity means the absence of self-alienation. In positive terms, the concept of authenticity is usually determined by reference to an "actual", "true" or "fundamental" self-image: Accordingly, a person who experiences themselves as authentic is in harmony with this self-image. One of the issues here is whether authenticity is integrated into the subjective perception of authenticity or whether there are criteria by which the authenticity of a person can be judged from the perspective of an independent observer. There is also considerable theoretical leeway with regard to the more precise definition of what constitutes a person's true self. The leading voices in the enhancement debate differ in particular on the question of whether the true self – understood as the practical identity that a person considers fundamental to themselves – is a given self that must be recognized in an act of self-discovery and then preserved, or whether it is rather the self freely chosen in an act of self-realization. The resulting notions of authenticity yield radically different evaluations of enhancement. Those who advocate the self-discovery model generally regard technical methods of self-optimization as influences that alienate their users from their given self. Proponents of the concept of self-realization, on the other hand, tend to welcome any support in the realization of personal self-development and therefore generally take a positive view of enhancement. The fact that both critics and proponents of enhancement can invoke the concept of authenticity to justify their respective positions reflects the normative ambiguity of this concept. In addition to the direction of impact, the clout of authenticity arguments is also a matter of controversy. First and foremost, they are presumably aimed at the individual, who should take them into account in their own well-understood self-interest. In contrast, the existence of an interpersonal enforceable duty of authenticity or a corresponding right to authenticity seems highly questionable.