M. Blyth

The term designer babies is a misnomer. It is not currently possible to alter genetic structures.

Designer babies
There is intense speculation in the media about the implications of geneticists' capacity to identify the functions of a growing number of genes. If, so the argument goes, it becomes possible to detect genes associated with certain physical features or behavioural patterns, abortion could be used for reasons that some people may consider to be trivial or grounded in prejudice. The fear is that prenatal screening and abortion might be employed not only to prevent disease and disability but also by prospective parents anxious to maximise their offspring's brains, beauty and conformity to conventional behavioural norms. So, despite broad consensus among scientists that there is no single gene responsible for intelligence, attractiveness or sexual orientation, anxiety about prenatal testing's potential for misuse remains strong. Why?

Designer babies: Emily Jackson challenges the concept of "designer babies." She explains the process of pre-implantation genetic diagnosis, which is what the media normally mean when referring to designer babies. (4:30 min)

One factor may be the tendency to use cartographic metaphors in order to describe the achievements being made by scientists working on the human genome project. If told that the human genome has been 'mapped', or that we now know the 'blueprint' for life, the lay person may understandably fail to appreciate that the functions of each gene will not be identified within the foreseeable future. In addition, the mixture of fascination and fear generated by the familiar image of the mad scientist creating humans to order clearly exercises considerable hold over the popular imagination. One recurring theme is the distinction commonly drawn between using new technologies to avoid illness and employing the same techniques for non-therapeutic reasons. Public opinion tends to differentiate sharply between doctors, who are generally assumed to be concerned only to prevent avoidable suffering, and scientists, whose amoral curiosity might propel them to attempt to 'play God'.

Accordingly, in relation to prenatal testing, sympathy for pregnant women who are at risk of passing on a debilitating genetic disease is contrasted with virulent condemnation of anyone who might choose to abort a fetus for a trivial or non-therapeutic reason. This distinction is clearly evident in relation to prenatal sex diagnosis, which can be used to prevent the birth of a child with a serious sex-linked disorder, such as Duchenne Muscular Dystrophy, but might also be employed by prospective parents who would prefer not to give birth to female offspring. Thus at the same time as science is lauded for reducing the incidence of pain and suffering, an identical technique is denounced for its potential to subvert the natural randomness of human reproduction. The assumption that greater human control over procreation will inevitably lead to its misapplication underpins much of the criticism levelled at prenatal genetic testing and other new reproductive technologies.

The disability lobby
There are several interrelated reasons why prenatal testing has attracted the attention of individuals who are concerned to promote the equal treatment of disabled people. First, one recurrent objection to abortion on the grounds of fetal abnormality is that it presupposes a crisp separation between normal and abnormal human development. Normality is not, on this view, an objectively determinable fact, but may instead embody a mutable set of cultural preferences. This sort of argument suggests that if there is no universal and objective definition of abnormality, the decision to have an abortion following a positive prenatal diagnosis must reflect dominant and thus challengeable social or medical assumptions about a particular disability. These critics of prenatal testing are therefore arguing that the decision to abort an abnormal fetus is socially constructed in the same way as it is where the fetus is the 'wrong' sex. So an individual who is shorter than normal may argue that it is not being short that makes their life more difficult than that of a person of normal height. Rather their problems are caused both by society's attitudes to physical disability, and by its failure to provide adequate services to accommodate their special needs.

Disability lobby: Emily Jackson discusses the arguments of the disability lobby against pre-implantation genetic testing and the abortion of abnormal fetuses. (4:20 min)

Related to this is the claim that offering prenatal testing when there is no plausible treatment for the particular condition creates a presumption in favour of termination. Pregnant women aged 35 and over are, for example, routinely offered either amniocentesis or chorionic villus sampling, both of which carry a risk of miscarriage that would not be worth taking unless termination would be contemplated in the event of a positive diagnosis. Critics of prenatal tests have therefore argued that their incorporation into standard medical practice creates powerful norms in favour of termination. It is, of course, true that a woman's decision to abort a fetus after a particular prenatal diagnosis is not taken in a vacuum, and may be shaped by both society's attitudes to disability, and by medical advice. It is not, however, obvious that the existence of external influences necessarily undermines the legitimacy of a particular choice. If this were the case, very few of our decisions would withstand scrutiny. Our preferences are always inevitably shaped by the social context in which they are formed but they are the only preferences we have and, provided that their satisfaction does not cause harm to others, they should be treated with appropriate respect.

	Thinking Points
	Do you agree with the use of pre-implantation genetic testing? Do you think that the abuse of such technologies is likely?

Of course, some members of the disability lobby would argue that prenatal testing and abortion does cause 'harm to others' through its negative consequences for disabled individuals. Just as certain feminists have suggested that sex-selective abortion devalues all women, this second type of argument suggests that the routine abortion of fetuses found to have a particular disability sends a message to people living with that condition that they should "not have been born". While clearly a powerful rhetorical device, this argument presupposes the moral equivalence of a fetus and a person. Disability should not be a legitimate reason for choosing between people, but a fetus does not have a legal personality and so rules that prohibit discrimination cannot be said to apply in utero. It is perfectly plausible to think that a disability makes a life less satisfying without believing that a person with that disability is less valuable. Analogously, if a 48-year-old woman decides to terminate an unexpected pregnancy, she is not presumed to be sending a message to all children with older mothers that they should not have been born. Rather she has taken a decision about the course of her life that only she is equipped to make. We should, I argue, allow a woman to assess for herself whether or not she wants to carry this particular pregnancy to term. The responsibilities of parenthood should be assumed voluntarily, and ought not to be imposed upon an unwilling pregnant woman.

Roslin Institute

Animals are selectively bred for certain characteristics. This is the litter of a Meishan and Large White cross showing segregation of genes for coat colour.

In a similar vein, some critics have expressed misgivings about the practical implications of increased resort to prenatal screening. In the absence of effective fetal therapy, prenatal tests can only promote infant health by enabling the abortion of abnormal fetuses, thus disease is prevented by selection, rather than by research into treatment and cures. As a result, it has been predicted that if there were fewer people living with disabilities, interest in devising new treatments and services for them would be correspondingly reduced. It has even been suggested that the state might have a compelling economic interest in the active promotion of prenatal testing because routine abortion of abnormal fetuses will be cheaper than funding the treatment and support needed by disabled people.

However, it is not clear that restricting women's access to prenatal diagnosis or abortion would in fact improve the lives of disabled people. Attempting to reduce the incidence of a particular disease is not necessarily incompatible with trying to improve the lives of people living with that condition. Currently many prospective parents who undergo prenatal or preconception genetic tests have family members or existing children living with a debilitating genetic disease. Their desire to avoid giving birth to another child with the same condition does not mean that they consider their ill relatives' lives to be without value, or not worth living. Nor does their willingness to have an abortion in the event of a positive diagnosis reflect their lack of interest in new treatments that might improve their lives of the affected members of their family.

	Thinking Point
	Do you think pre-natal screening and abortion on the grounds of fetal abnormality has negative implications and consequences for disabled individuals?

A third and related criticism of prenatal tests is that their routine use might create new standards of perfection, or make physical or mental incapacity appear to be effectively optional. These concerns have considerable resonance with disability activists' objections to the growth of a perceived "tyranny of perfection". Bill Hughes, for example, argues that prenatal genetic testing presupposes both the existence of a "genetic hierarchy" and the categorisation of disabled individuals as "sub-standard human beings". Since wealthier women tend to have more prenatal tests, even where there is no charge for screening, it has also been argued that certain diseases will increasingly correlate with socio-economic status, leading to the creation of a "biological underclass".

The chief defect of all of these arguments is that they massively overstate the social changes that could be wrought by advances in prenatal testing and abortion. New prenatal tests are highly unlikely to transform attitudes to disability because most diseases and disabilities are not caused by genetic abnormalities detectable in utero, but instead result from poverty, accidents, war, exposure to environmental toxins, or from a complex interaction between an individual's genotype and their environment.

Genetic risks
Until recently, the only way in which the birth of a child suffering from a particular abnormality could be prevented was through prenatal diagnosis of an existing fetal handicap. After a positive conventional prenatal test result, the decision may be emotionally fraught, but it is comparatively simple to understand: if this pregnancy were to be carried to term, the resulting child would have the identified disability. If the prenatal test reveals an abnormal gene, on the other hand, this does not necessarily mean that the child will develop a particular condition. Some genetic tests can predict with certainty that a child's life would be both short and excruciatingly painful, and may, for practical purposes, be largely indistinguishable from a conventional diagnosis of abnormality. Others, however, may identify a predisposition to an adult-onset disease, or may indicate there would be some statistical risk that the resulting child would suffer from a particular abnormality.

Gene penetrance, for example, varies. BRCA1, which is associated with breast cancer, has a penetrance of 85 percent, meaning that in 15 percent of women this particular gene will not lead to breast cancer. Some genes may increase an individual's susceptibility to a particular environmental toxin, thus possibly leading to future ill-health if certain environmental factors are present. In addition, tests are often unable to predict both the severity of the disability, and the age of onset. So although it is possible to identify the genetic mutation associated with cystic fibrosis, we do not yet know how to tell whether or not the individual will be gravely affected.

	Gene Terms
	Penetrance Gene penetrance is the likelihood that a condition will develop when a given gene known to produce this disorder is present. Expressivity Gene expressivity is the range of variation with which a trait appears in an individual carrying a certain gene. e.g. whether conditions have severe or mild symptoms. Genotype Genetic constitution of an individual usually in reference to a single gene or set of genes. May also refer to a person's entire genetic make up. Phenotype Observable physical or biochemical characteristics of an individual. e.g. hair or eye colour.

It is, therefore, true both that a prenatal genetic diagnosis will often be much more uncertain than results obtained through conventional diagnostic techniques, and that this uncertainty makes it particularly difficult to digest the results of prenatal genetic tests. It is especially difficult for an individual to interpret a diagnosis expressed in terms of risk because probability may only make sense at a macro level. The significance of a statistical risk to one's health is almost impossible to grasp, because as far as each individual is concerned the material risk is actually either 100 percent or 0 percent: they will or will not develop the particular condition. Since a variety of external factors inevitably feed into our perception of a particular risk, the concept itself may even be essentially meaningless without its subjective and contextual interpretation. For example, the idea that traits 'run in the family' is not new, and so popular understandings about the heritability of certain talents, weaknesses or characteristics will shape people's understanding of genetic risk. Similarly, individuals faced with a positive prenatal genetic diagnosis may understand it in terms of some resolutely pre-modern concepts such as fate or destiny.

Probabilistic information about a fetus's susceptibility to future ill-health thus converts prenatal diagnosis from a description of current handicap into something much more uncertain. Test results that tell us about possible futures thus blur the boundary between illness and health and undermine the clear-cut opposition between good and bad outcomes, which instead may co-exist in a diagnosis that shows no current infirmity, but some increased susceptibility to a late-onset condition.

Freeman publishers

Tissue cultures obtained via amniocentesis can be used to detect genetic abnormalities in fetuses.

The analysis of risk has become a central theme in some strands of sociological theory. Risk has ceased to be a neutral description of the expected frequency of a particular outcome, and has instead become a symbol for the subjective uncertainties created by rapid modernisation. Since risks tend to seem especially threatening if the feared adverse outcome is unfamiliar, uncontrollable or unpredictable, it is probably unsurprising that the uncertainties that emerge from biotechnology, and in particular from genetic knowledge, have appeared to offer a rich source of examples for sociologists interested in the implications of newly emerging risks. For instance, Beck has suggested that "reproductive medicine and genetic research throw open the door to a new quality of politics", and according to Giddens, the choices offered to pregnant women by modern science and technology are opening up "new ethical spaces". Our unprecedented capacity to control reproductive outcomes is therefore accompanied by the fear that this new technology may itself be uncontrollable.

The modernist assumption that scientific progress is a source of unmitigated health benefits, though still prevalent among scientists, has thus been challenged by sociologists concerned about technology's potential to create unforeseeable hazards. While it is undeniable that genetic test results introduce new ambiguities into the diagnosis of disease, it is less clear that they present potentially uncontrollable dangers. Nor is it obvious that the regulation of prenatal genetic testing needs to be informed by the 'precautionary principle' as is commonly advocated in relation to other uses of biotechnology, such as genetically modified food or nuclear power. Prenatal genetic test results may present individual pregnant women with information that is more ambiguous than a conventional diagnosis, but it does not necessarily follow that prenatal genetic testing has dangerously uncertain implications for society as a whole.

Unjustified fears?
Currently, routine prenatal genetic testing is impracticable, but it is of course possible that new developments will increase the feasibility of comprehensive, population-wide screening. A further and less transient reason to question the various fears that have crystallised around the issue of prenatal genetic testing is that they rely upon a distorted understanding of genetics. In the following sections, I argue that an exaggeration of the dangers posed by genetic screening is thrown into particularly sharp relief by the relative indifference we display towards certain other health risks.

Public understanding: Emily Jackson discusses the public understanding of genetics. She argues that people over-estimate the significance of genetic information in comparison with other causes of ill-health. (3:50 min)

There are two practical reasons why comprehensive and routine prenatal genetic testing is currently impossible. First, the principal ways to obtain samples of fetal tissue are invasive and carry a comparatively high risk of miscarriage. As a result, prenatal genetic testing is used only where the fetus is judged to be at increased risk of a particular condition as a result of a specific indication, such as a relevant family history. Research into the possibility of isolating fetal cells from a pregnant woman's blood sample is ongoing, and if successful would undoubtedly facilitate some universal testing.

The second practical problem is that there are so many genetic abnormalities that it would simply be impossible to screen for all of them, and the tests that are currently available presuppose that a clinical team knows which condition they are trying to detect. Existing knowledge about a particular fetus's increased susceptibility to a specific abnormality is then a precondition for prenatal genetic testing. Although there are far too many genetic disorders for a single test to ever be able to screen for all of them, in the near future new diagnostic techniques will allow universal screening for some of the most common conditions, such as cystic fibrosis. But while the practical obstacles that have so far prevented routine prenatal genetic testing will eventually be removed, at least in part, there are other more permanent reasons to question the empirical base of the various anxieties associated with prenatal genetic testing.

Genetic determinism
There are a few diseases, such as Huntington's chorea, for which prenatal identification of an abnormal gene provides a decisive diagnosis. Because Huntington's disease is monogenic, that is it is caused only by this abnormal gene, its elimination is conceivable. If all fetuses with the genetic mutation that causes Huntington's disease were to be aborted and no babies were born with the relevant gene, it could not be passed on to the next generation and would disappear. Huntington's disease is therefore commonly cited as an example of the revolutionary possibilities being opened up by prenatal genetic screening.

	Genetic Disorders
	Cystic Fibrosis Inherited disorder of the exocrine gland, caused by a genetic abnormality that results in the disruption of chloride transfer across membranes. Consequently chlroide ions build up in the cells of the lungs and other organs. Huntington's Disease Rare hereditary disease of the basal ganglia and cerebral cortex, resulting in chaotic movements, intellectual deterioration, and psychosis. All American patients are thought to descended from two brothers with Huntington's disease, who migrated to the US from England. No effective treatment is known. Duchenne Muscular Dystrophy A form of muscular dystrophy that affects males only. Muscle-based breathing and heart problems cause death for most patients by their early twenties. The disease is caused by a genetic error that prevents the body from producing dystrophin, a protein that normally occurs in muscle tissues.

Single gene disorders like Huntington's are, however, extremely rare, and they are the only ones for which a simple genetic 'solution' is feasible. Most diseases can be the result of the interaction between several genes; and/or the interaction between an individual's genotype and their environment; or they may be triggered solely by environmental factors. So although genetic markers for certain cancers have been identified, 95 percent of people who develop colon or breast cancer do not have the particular genetic mutation that has been associated with an increased risk. Prenatal screening for a genetic predisposition to cancer would thus have minimal impact upon its population-wide incidence. Similarly, an individual's learning difficulties may be the result of a genetic disease; or environmental factors such as inadequate nutrition, care or education; or it may be caused by a combination of genetic susceptibility and environment. Inordinate interest in the genetic origins of mental disorder might therefore deflect attention from less intriguing but perhaps more statistically significant causes like poverty and childhood deprivation.

It is undeniable that reducing poverty levels would radically alter the physical and mental health of the population to an extent unimaginable through prenatal genetic testing and abortion. Indeed a prenatal test that was capable of predicting future poverty would also represent a fairly accurate predictor of future ill health. Yet it is perhaps interesting that this sort of knowledge is not perceived to be especially disturbing or threatening. Why are we so fearful about our capacity to single out certain individuals who present a genetic risk, and untroubled by our parallel ability to make predictions about the ill health likely to be suffered by children born into poverty? Like fear of crime, public perceptions of risk in relation to genetics appear to bear little relationship to the actual probability of certain adverse events occurring. Of course, to acknowledge the practical limitations of prenatal genetic screening is not to understate its value and importance for individuals who are at risk of passing on a debilitating genetic disorder. Moreover, misplaced fears about eugenic selection and designer babies should not be allowed to deflect attention from some of the important policy issues that may be raised by prenatal genetic diagnoses.