By Hannah Rahim
New technologies are increasing the accessibility of polygenic embryo screening, which can assess the likelihood of an embryo developing polygenic diseases (e.g., diabetes, schizophrenia) or provide insight into certain polygenic traits (e.g., height, intelligence). This procedure has many complex clinical, social, and ethical implications, but is currently unregulated in the U.S.
Orchid Biosciences and Polygenic Embryo Screening
In December 2023, the start-up company Orchid Biosciences launched a genetic testing service that enables prospective parents undergoing in-vitro fertilization (IVF) to screen embryos and identify genetic predispositions to common diseases. Prospective parents can then select the most desirable embryo to be used for pregnancy. Orchid claims that it can sequence more than 99% of an embryo’s genome to test for both monogenic diseases (caused by mutation of a single gene) and polygenic diseases (caused by the combined action of multiple genes). Orchid’s testing service has sparked debate about the utility and consequences of polygenic embryo screening.
Until recently, pre-implantation genetic testing of embryos was limited to severe or life-limiting monogenic diseases, such as cystic fibrosis or muscular dystrophy. Orchid’s testing for common polygenic diseases, such as coronary artery disease, diabetes, and bipolar disorder, is more controversial in part because of the technological complexity of predicting a condition arising from multiple genes, which results in a low predictive power of polygenic scores. Researchers and professional biomedical organizations have expressed concerns about polygenic risk scores, such as the fact that they do not determine whether someone will develop a condition and only measure possible risk factors. Also, polygenic risk data are not specific to one condition, thus selection for one condition can affect other genetic traits.
Despite these concerns, recent research found that 72% of the American public approve of polygenic embryo screening and 82% would be interested in using polygenic embryo screening if already undergoing IVF. Currently, companies like Orchid only offer polygenic embryo screening for disease conditions, but polygenic testing methodologies can also be used for non-disease traits. Public approval for polygenic embryo screening is much higher for physical health conditions (e.g., prostate cancer) (77%) and psychiatric health conditions (e.g., Alzheimer’s) (72%) than for behavioral traits (e.g., intelligence) (36%) and physical traits (e.g., height) (30%).
Ethical Implications of Polygenic Embryo Screening
Polygenic embryo screening engenders complicated and challenging ethical considerations. The procedure is expensive and not covered by insurance (Orchid’s genetic test will cost consumers $2,500 per embryo, not including the costs of IVF), which has led to concerns about perpetuating wealth inequalities. In the words of philosopher Peter Singer, “the present generation of wealthy people will have the opportunity to embed their advantages in the genes of their offspring.” Relatedly, the option to create a “designer baby” by selecting an embryo based on a variety of screened characteristics can lead to a consumerist approach to reproduction, which can have consequences for the parent-child relationship. For example, people have expressed concerns about hyper-parenting in the selection of embryos based on certain traits. If polygenic embryo screening is offered for behavioral traits, some parents may select an embryo based on traits they value like athleticism or academic achievement, and impose pressure on their children to pursue activities in line with these traits.
Polygenic embryo screening is also susceptible to an expressivist critique – that selecting against certain traits may imply a lower worth of individuals who possess selected-against traits and can increase stigma surrounding those traits. This critique can be rebutted by arguing that screening is a preventative health measure and that preventing the incidence of a condition does not imply a negative view towards individuals with that condition. For instance, vaccinating against a disease does not make a negative judgment about individuals with the disease.
This expressivist critique is related to concerns of disability rights advocates that screening embryos for disabilities results in a harmful view of disabilities. Their concerns span beyond attitudes towards individuals living with disabilities and instead, focus on the argument that screening reinforces the mistaken belief that disability itself is a problem to be solved. Many disability rights advocates argue that the negative aspects of life with a disability are attributable to societal discrimination rather than the medical condition itself. They therefore see disability as just another form of human variation, like sex or race, and not something to be prevented. Additionally, while embryo screening may determine the risk of a child experiencing a particular disability, it cannot predict a child’s quality of life with that disability. People without disabilities often perceive the quality of life of those with disabilities as much lower than it actually is – many people with disabilities report a similar quality of life to people without disabilities. Embryo screening for disabilities thus often does not reflect the views of individuals living with those disabilities.
Regulation of Polygenic Embryo Screening
The complex clinical and ethical implications of polygenic embryo screening emphasize the need for appropriate regulation. In the U.S., embryo testing and selection are unregulated and governed solely by individual clinicians and market forces. This approach contrasts with countries like France, Switzerland, Italy, UK, and Australia which limit embryo selection to the avoidance of disease characteristics. The UK maintains a list of conditions that can be tested for, while Australia allows for the testing of diseases that “severely limit quality of life.” A limitation of a disease-based model is that the distinction between “disease” and “normality” can sometimes be arbitrary, as alluded to in the disability critique above.
One regulatory model that has been proposed is the welfarist model, which allows for the selection of any trait if it is associated with a reliable increase in expected well-being. This model reflects the evolving nature of embryo screening to encompass polygenic traits that may not be limited to disease states. However, well-being can be influenced by the intersection of personal traits with social structures. Therefore, a problematic interpretation of this model could allow for the selection of embryos based on sex or race on the grounds that prejudice and discrimination associated with these traits can diminish well-being. If a welfarist model were to be adopted, it would need to be accompanied by a philosophical analysis of what constitutes “well-being” and a scientific analysis of the relationship between well-being and various genetic traits.
The rise in polygenic embryo screening is ushering in a new era of human control over reproduction. As technological and commercial developments are outpacing ethical and policy discussions, reflecting on the consequences of polygenic screening, and considering potential regulatory models is critical.
