Bioethics Forum Essay
Polygenic Embryo Screening: Ethical and Legal Considerations
Last month, Bloomberg reported on what seems to be the first child born following a new kind of genome-wide screening. Four embryos were screened, and the embryo selected for implantation was the one given the best genetic odds of avoiding heart disease, diabetes, cancer, and schizophrenia in adulthood. The test, called polygenic embryo screening, was performed by Genomic Prediction, a company in New Jersey.
The news has been met with concerns about the degree of control we may now have over future generations. While Genomic Prediction did not screen for intelligence or other non-disease traits, it is possible to do so, and this raises questions about eugenics and designer babies.
In this essay, we consider the ethical case for using polygenic scoring to select embryos that possess the best chance of a healthy life, as well as the need for regulation.
Polygenic embryo screening uses an algorithm to summarize the estimated effect of hundreds or thousands of genetic variants associated with an individual’s risk of having a particular condition or trait. It differs from more routine forms of embryo screening such as preimplantation genetic diagnosis (PGD), which detects single gene variants associated with a disease or trait. Polygenic scoring is not as precise as PGD, since it only represents an embryo’s risk of a particular condition or trait.
Polygenic embryo screening is essentially unregulated in most countries and is, therefore, available to prospective parents. Many countries that regulate genetic testing in general permit it only it for genetic disorders and conditions. In South Africa, for example, embryonic screening is governed by the regulations of the National Health Act. However, these regulations only specifically refer to one genetic trait – sex – and state that it can only be identified for purposes relevant to the health of the embryo. Since polygenic embryo screening itself is not regulated, parents may request it as an add-on the in vitro fertilization based on their right to make decisions concerning reproduction, or reproductive autonomy, which is guaranteed by the South African constitution.
Most European countries have legislation that restricts genetic testing to major diseases, such as beta thalassaemia. It is not clear whether an elevated probability of a disease would count. For example, in the United Kingdom, embryonic screening falls under the purview of the Human Fertilisation and Embryology Authority, which issues licences for preimplantation genetic testing. Licences are permitted to screen embryos against serious genetic diseases and sex-linked diseases, to identify tissue-compatible embryos, or to establish biological parentage.
Some concerns over using polygenic embryo screening are based on science. For instance, the score indicates the probable risk of a future child developing a certain condition, but it does not guarantee that this will be the case. Other concerns are based on ethics. If we consider one disease that polygenic embryo screening has been used for – heart disease – it is arguable that such screening is an extreme intervention. Heart disease is treatable and preventable; individuals can reduce their risk of heart disease through environmental management such as monitoring their diet. This raises the question of whether it is ethical to select against embryos with an increased probability of developing heart disease later in life when the condition can be managed. On the other hand, it can be argued that polygenic embryo screening would impact public health positively by reducing the burden on health care systems. It could be considered unethical not to use this technology as it would offer future generation the prospect of healthier lives. We may be morally obligated to check the polygenic risk scores of embryos and select the embryos with genetic traits that indicate the best prospect of quality of life.
Polygenic testing of embryos is currently offered by Genomic Prediction, MyOMe, and Orchid. It is available only to those with the ability to pay thousands of dollars. This raises the possibility of increasing inequality as the rich have babies with greater odds of good health and, potentially, other gifts and talents. However, increasing inequality is not inevitable. It is essential that, just as people have a right to basic health care, they also have a right to basic reproductive selection that is important to health and well-being. European countries are well placed to position this new revolution within state funded universal health care, but the demands of justice may be more difficult to meet elsewhere in the world.
Polygenic embryo screening has the potential to give babies a health advantage, but it may also be used to “score” embryos for social, or non-disease-based advantages. This raises the spectre of eugenics. For this reason, and to guard against misuse of the technology, broad discussion is needed around what advantages we would be prepared to allow to proliferate in future people. Some favor a regulatory model that would permit polygenic screening if it is correlated with increased odds of greater well-being. This would require a philosophical and ethical analysis of what constitutes well-being and a scientific analysis of the correlation between polygenic screening and that outcome. Societal discussion about these issues is necessary, too. Should genetic variants associated with diseases and non-disease traits be considered? Is there a difference, ethically, between justifying the selection of physical traits, such as eye color, and functional traits, such as intelligence, based on their potential to increase the well-being of a future person?
Regulation of polygenic embryo screening should explore these questions and address issues of justice and inequality. Crucially, regulators should make the technology broadly available, so that reaping its benefits does not depend on the ability to pay. Regulation should also ensure that screening that improves general health and well-being would be permitted.
Sheetal Soni (@Sheetal_Soni) is a senior lecturer at the University of KwaZulu-Natal in South Africa. Julian Savulescu (@juliansavulescu) is Director of the Oxford Centre for Neuroethics, Uehiro Chair in Practical Ethics at the University of Oxford, and a Hastings Center fellow.