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editorial
. 2022 May 23;37(7):1375–1378. doi: 10.1093/humrep/deac110

Polygenic embryo screening: four clinical considerations warrant further attention

S Pereira 1,✉, S Carmi 2, G Altarescu 3, J Austin 4, D Barlevy 5, A Hershlag 6,7, E Juengst 8, K Kostick-Quenet 9, E Kovanci 10, R B Lathi 11, M Mukherjee 12,13, I Van den Veyver 14,15, O Zuk 16, G Lázaro-Muñoz 17,18,a, T Lencz 19,20,21,a
PMCID: PMC9247413  PMID: 35604365

ABSTRACT

Recent advances in developing polygenic scores have made it possible to screen embryos for common, complex conditions and traits. Polygenic embryo screening (PES) is currently offered commercially, and though there has been much recent media and academic coverage, reproductive specialists’ points of view have not yet been prominent in these discussions. We convened a roundtable of multidisciplinary experts, including reproductive specialists to discuss PES and its implications. In this Opinion, we describe four clinically relevant issues associated with the use of PES that have not yet been discussed in the literature and warrant consideration.

Keywords: polygenic risk scores, PRS, polygenic embryo screening, trait screening, genomic risk scores, embryo screening, genetic screening

Recent advances in developing polygenic scores for complex conditions and traits have made it possible to test embryos for risk of common conditions, such as diabetes, cancers and psychiatric disorders, among others, as well as for traits like height and intelligence quotient (IQ). Polygenic embryo screening (PES) is currently offered commercially, and its recent emergence has generated wide media coverage (Metzl, 2019; The Economist, 2019; Davis, 2021; Hercher, 2021; Lopez Lloreda, 2021), as well as a number of papers assessing its potential utility (Karavani et al., 2019; Treff, 2020; Treff et al., 2020a). Several researchers, including ourselves (G.L.-M., S.P., S.C., and T.L.), have explored the ethically relevant aspects of this new technology, such as the limited applicability of PES for those of non-European ancestry; the additional cost burden of using IVF and PES making it unaffordable for many; the potentially misleading manner in which polygenic risk information may be presented (i.e. relative vs. absolute risk reduction; see below); and the ability to screen for multiple conditions and traits at the same time, which may include problematic phenotypes such as stigmatized disorders, desirable traits and conditions for which lifestyle adjustments could meaningfully reduce risk (Lázaro-Muñoz et al., 2021; Lencz et al., 2021; Munday and Savulescu, 2021; Tellier et al., 2021; Turley et al., 2021). These aspects of PES raise salient ethical questions. Should there be oversight as to which conditions and traits are included in these tests and, if so, by whom? What degree of uncertainty in test results is acceptable? Will the use of PES primarily by those with means and those for whom polygenic risk scores (PRS) are more accurate (typically those of European ancestry) further exacerbate existing inequalities? How do we as a society decide what it means to be born healthy? Could PES lead to further discrimination against those with stigmatized conditions? Might the use of PES lead to devaluing human diversity? While we do not directly address these ethical issues in this piece, we want to emphasize the importance of continuing discussions on these topics.

Surprisingly, reproductive endocrinologists and infertility specialists (REIs), who would potentially be those offering and managing PES in the clinical setting, have largely not yet been involved in these discussions. Consequently, we held a roundtable to bring together REIs, ethicists, social scientists, lawyers, geneticists and genetic counselors to discuss PES. The meeting was largely informal, intending to promote discussion and serve as a first step in gauging the most salient clinical issues. Perceptions of PES varied considerably amongst roundtable participants. In fact, at least one roundtable participant felt that PES is not currently ethically or morally acceptable, and some questioned whether the discussion of clinical challenges of PES was premature given concerns about its current utility and ethical permissibility. However, as PES is already commercially available, clinical considerations may add substantively to ongoing discussions about PES.

The following does not represent a consensus opinion, but rather describes four clinically relevant, non-mutually exclusive issues identified by our multidisciplinary group, that have not yet been discussed in the literature and warrant consideration: (i) the expansion of who seeks ART services and the downstream consequences of that expansion for clinical practice as well as society; (ii) REIs offering or acceding to patient requests for PES despite their skepticism of whether there is sufficient evidence to support its clinical use; (iii) predicted disagreements between REIs and intended parents about how to use PES, which could lead to friction in the clinician–patient relationship; and (iv) offering PES may necessitate changes in REIs’ practices.

The first clinically relevant consideration our roundtable identified is that PES may lead to a significant change in who seeks ART services. Currently, IVF is typically used by infertile individuals or couples, those who wish to prevent the risk of monogenic disease (via preimplantation genetic testing; PGT-M), and those who need to use IVF to have a child for another reason (e.g. same-sex couples, those who have used fertility preservation techniques, etc.). The use of PGT has been increasing in both the USA and Europe, though it still accounts for a minority of all IVF procedures (European IVF-monitoring Consortium (EIM) for the European Society of Human Reproduction and Embryology (ESHRE) et al., 2020; Roche et al., 2021; van Montfoort et al., 2021). Given the recent emergence of PES, there is now the potential for individuals or couples who would not otherwise have used IVF to seek it out in order to utilize PES. Our roundtable explored a number of motivations for PES that could lead to potential new ART patients. Some intended parents may be persuaded by the commercial marketing and discourse that frames the choice to use PES as an informed and responsible approach to reproduction (Hercher, 2021; LifeView, 2021; ORCHID Embryo Report, 2021; Timpson, 2021). Others’ interest, however, may be driven by recent evidence supporting potential large relative risk reductions that could be achieved by PES across multiple diseases (Treff et al., 2020b). Like those using PGT-M to prevent the risk of monogenic conditions, PES would allow those with a history of polygenic conditions to screen and transfer embryos with lower risk for those conditions (e.g. Crohn’s disease, type 1 diabetes, schizophrenia; Lencz et al., 2021). These parents may see PES as a valuable opportunity to give their future child the best possible chances of avoiding some health conditions, even while recognizing the potential limitations and the fact that absolute risk reductions are modest at best (Lencz et al., 2021; Turley et al., 2021).

If the availability of PES does lead to new users of IVF, there may be downstream consequences for both clinical practice and society. For example, widespread adoption of PES could significantly increase the number of viable embryos created and ultimately not transferred for implantation. Though the issue of non-transferred embryos is not new in reproductive medicine, it could become more complicated when there are significantly more unused embryos, and information about those embryos’ risk of polygenic conditions is available. Could these embryos be viewed as inferior in some way? Could the children subsequently born from them face stigmatization or discrimination (e.g. by insurance companies) related to their identified higher risk of polygenic conditions? On the other hand, might PES create a market for leftover embryos considered to have desirable polygenic scores (Sandel, 2007)?

Increased use of IVF would also put patients at additional risk and add burden to clinics. IVF is not entirely risk-free (Zhang et al., 2019; Li et al., 2021; Makhijani et al., 2021), and thus, those opting for IVF to use PES would open themselves up to these additional risks. Decisions about whether to use IVF solely to use PES should weigh the risks of IVF to the mother and child, including risks of prematurity, multiple births, birth defects, cardiac defects and pregnancy complications, against the potential benefits of PES. Roundtable participants agreed that REIs may find themselves facing these difficult decisions as they counsel intended parents about their choices unless additional professional policies or practice guidelines can help them anticipate and manage these challenges. In addition, a PES IVF cycle generally requires pretest genetic counseling, intracytoplasmic sperm injection, embryo biopsy, sample shipping, embryo freezing, post-test counseling and frozen embryo transfer, and thus, additional needs for staffing, training, equipment, space and time in the clinic. Moreover, some intended parents may choose to undergo multiple cycles to get their desired embryo(s), adding further burden.

The second clinically relevant consideration is that REIs may offer or accede to patient requests for PES before they believe there is robust evidence to support routine clinical use. Our roundtable identified several reasons why REIs may choose to offer PES. First, as some of the companies’ marketing PES commercially use a patient-initiated, clinician-ordered model for their products, patient demand may lead some clinics to begin offering PES; even REIs who may have otherwise not chosen to offer PES may feel competitive pressure to do so, as PES becomes more widely known. Second, some REIs may choose to offer PES now despite their skepticism of its current utility because they feel it will eventually become common practice. Third, as observed elsewhere in the uptake of newborn genomic sequencing (Pereira and Clayton, 2018), the technological imperative—the drive to use novel technologies merely because they are new and viewed as improvements over previously available techniques—can be a powerful driver of technology adoption (Koenig, 1988; Hofmann, 2002). Finally, if PES does become more commonly offered and used, it is possible that even the most skeptical of REIs may feel obligated to make PES available to their patients to avoid potential future liability for not offering this additional risk screening. These varied motivations predicted by our roundtable contributors portend a future in which there is great variation in where and how PES is offered, especially in the absence of formal guidelines or consensus recommendations.

The third clinically relevant consideration is that REIs and intended parents may disagree about how to use PES, which could lead to friction in the clinician–patient relationship. PES is expected to be effective for conditions with highly powered genome-wide association studies (GWAS). Yet, these conditions may not be the same as those for which parents may wish to screen their embryos. For example, many parents may be interested in screening their embryos for risk for autism, but PRS for autism have limited power (in terms of variance accounted for; Grove et al., 2019), and do not take into account rare genetic variants, which play an important role in autism susceptibility (Wilfert et al., 2021). Indeed, the available GWAS data may not even align with what parents may think of as being ‘healthy’, and what counts as a healthy baby may vary between parents, as well as across cultures. PES may lead to disagreements between REIs and parents as to which embryo is ‘healthiest’ based on all the available information. For instance, REIs may wish to prioritize embryos for transfer based on morphology, while parents may be more concerned about risks of certain polygenic conditions. Parents may conceptualize risk differently than REIs, driven by their perceptions of polygenic conditions and other salient context (e.g. family history) (Austin, 2010). Parents may also want to select for traits, such as height or IQ, or even a specific condition (e.g. deafness), strategies with which many REIs may disagree. Alternatively, if all embryos in a cycle are found to be at high risk for polygenic conditions, parents may still want to transfer one or more of those embryos irrespective of risk rather than complete another cycle, which may be at odds with clinic-specific practices (e.g. some clinics do not permit the transfer of embryos that test positive for monogenic risk, such as BRCA1/2 pathogenic variants).

The fourth clinically relevant consideration is that offering PES may necessitate changes in REIs’ practices. Though the companies offering PES typically also offer some counseling, patients will likely expect their REIs to help them understand and make decisions about the results of PES. This could lead to changes in how REIs counsel their patients. Counseling patients on PES results should carefully balance known risks and costs of IVF with potential benefit to potential offspring, which will take considerable clinical time, a precious resource given rapidly expanding demand for these services. Our roundtable was particularly concerned about how PES results could be adequately communicated to patients. As others have noted, it is important that PES results emphasize absolute risk reduction vs. relative risk reduction (Turley et al., 2021) to help parents put this information into context. For example, we (S.C., T.L. and O.Z.) previously estimated that the relative risk reduction to be achieved by using PES for schizophrenia is nearly 50% (Lencz et al., 2021). However, this translates to absolute risk reduction of, at most, 0.5 percentage points. Though some groups of clinicians, such as genetic counselors, specialize in the communication of complex genetic risk-related information, there are well-documented concerns about the inadequacy of the size of this workforce; these concerns would only be exacerbated by the potential increase in demand that could be associated with the widespread use of PES (Hoskovec et al., 2018). Given this and the societal reality of low numeracy (Gigerenzer et al., 2007), REIs may face challenges explaining PES results effectively and efficiently. Furthermore, approaches to counseling patients vary widely between practices. For example, some have psychologists on staff while others do not. This could lead to substantial variation in the information patients receive about the technology, their options and the consequences of using PES.

The four clinical considerations we have raised may additionally challenge the current balance between professional medical judgment and patient preferences. Reproductive medicine has typically, within reason, prioritized patient preferences out of respect for reproductive autonomy. The advent of PES, especially in the absence of professional guidelines to support its routine clinical use, may cause some REIs to rethink that balance. Given that reproductive autonomy is a core value in reproductive medicine, as well as within our larger social context, any change to this balance may be particularly fraught.

These issues, alongside other important ethical concerns raised by us and others elsewhere (Lázaro-Muñoz et al., 2021; Turley et al., 2021), highlight the critical need to bring more people together to discuss PES and its potential implications, especially given that it is already commercially available. Indeed, this piece may have only uncovered a subset of the challenges PES may generate. Our roundtable of a group of multidisciplinary experts is a valuable first step in this goal, but further work must be done, including developing approaches to promote ethically informed practices when utilizing this technology. Because PES goes to the core of how we, as a society, define health and disease and their values even before birth, we need ongoing discourse across disciplines and social roles. This discourse should include a wide range of REIs, as well as additional voices such as other clinicians, intended parents, patient advocates, bioethicists, geneticists, genetic counselors, policymakers and industry representatives. Professional guidelines and consensus recommendations for best practices are urgently needed.

Authors’ roles

S.P., S.C., G.L.-M. and T.L. led the conception, development and oversight of the work and agree to be accountable for all aspects of the work. G.A., J.A., D.B., A.H., E.J., K.K., E.K., R.B.L., M.M., I.V.d.V. and O.Z. made substantial contributions to the conception of the work, revised the work critically for intellectual content, gave final approval for the work and agree to be accountable for all aspects of the work.

Funding

This work was supported by the National Human Genome Research Institute of the National Institutes of Health, grant R01HG011711 (T.L., S.C. and G.L.-M.). The views expressed are those of the authors alone and do not necessarily reflect views of the NIH or the authors’ affiliated institutions.

Conflict of interest

S.C. reports consulting fees from MyHeritage, a direct-to-consumer DNA testing company, which also offers polygenic risk scores. The company does not work on preimplantation genetic testing and was not involved in the development of this manuscript in any way. The remaining authors declare no conflicts of interest.

Contributor Information

S Pereira, Center for Medical Ethics and Health Policy, Baylor College of Medicine, One Baylor Plaza, MS420, Houston, TX 77030, USA.

S Carmi, Braun School of Public Health and Community Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel.

G Altarescu, Preimplantation Genetic Unit and lysosomal Clinic, Medical Genetics Institute, Shaare Zedek Medical Center, Hebrew University, Jerusalem, Israel.

J Austin, Departments of Psychiatry and Medical Genetics, University of British Columbia, Vancouver, BC, Canada.

D Barlevy, Center for Medical Ethics and Health Policy, Baylor College of Medicine, One Baylor Plaza, MS420, Houston, TX 77030, USA.

A Hershlag, Renaissance School of Medicine, Stony Brook University, Stony Brook, NY, USA; Zucker School of Medicine, Hofstra University, Hempstead, NY, USA.

E Juengst, Center for Bioethics, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.

K Kostick-Quenet, Center for Medical Ethics and Health Policy, Baylor College of Medicine, One Baylor Plaza, MS420, Houston, TX 77030, USA.

E Kovanci, Houston Assisted Reproductive Technologies (HART) Fertility Clinic, The Woodlands, TX, USA.

R B Lathi, Stanford University, Stanford, CA, USA.

M Mukherjee, Center for Medical Ethics and Health Policy, Baylor College of Medicine, One Baylor Plaza, MS420, Houston, TX 77030, USA; Department of Sociology, University of Califorinia, Berkeley, Berkeley, CA 94720 USA.

I Van den Veyver, Department of Obstetrics and Gynecology, Baylor College of Medicine, Houston, TX, 77030, USA; Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, 77030, USA.

O Zuk, Department of Statistics and Data Science, The Hebrew University of Jerusalem, Jerusalem, Israel.

G Lázaro-Muñoz, Center for Bioethics, Harvard Medical School, Boston, MA, USA; Department of Psychiatry, Massachusetts General Hospital, Boston, MA, USA.

T Lencz, Departments of Psychiatry and Molecular Medicine, Zucker School of Medicine at Hofstra/Northwell, Hempstead, NY, USA; Institute of Behavioral Science, Feinstein Institutes for Medical Research, Manhasset, NY, USA; Division of Psychiatry Research, Zucker Hillside Hospital, Glen Oaks, NY, USA.

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