Public Comment: Lozier Institute on NIH’s Request for Information on Reducing Reliance on Human Embryonic Stem Cells in NIH-Supported Research

On April 24, 2026, the Charlotte Lozier Institute’s Director of Life Sciences, Dr. Cameron Louttit, submitted a public comment on behalf of CLI in response to the NIH’s notice NOT-OD-26-031, in which it paused new submissions to the Human Embryonic Stem Cell Registry and requested information on reducing reliance on human embryonic stem cells in NIH-supported research. Below, CLI’s comment is reproduced in full.

To Whom it May Concern:

The Charlotte Lozier Institute applauds the decision to re-evaluate federal funding for human embryonic stem cell (hESC) research and respectfully urges the NIH to prohibit its further funding, allocating this support instead to promising endeavors that do not put Americans in moral conflict.

The history of hESC research is one of remarkable promises and pressures. Since its earliest days, assertions of “miracle cures” have been routinely used to pave over public and private concerns about this work. Of course, those “miracle cures” have not materialized as proposed, and the reality of over-promising both to secure funding[1] and to appease political and social demands[2] has been well detailed. But over 25 years’ worth of attributing unique, curative, and indeed miraculous potential to these cells has, inevitably, left a lasting imprint. External and internal pressures abound to subjugate ethical concerns to scientific potential, both at an individual and a public level.

But this is not an effective strategy to resolve such matters.[3] The reality is that the substantial public and private discomfort with hESCs, evident from the earliest public discussions on their use, has not gone away. Such discomfort is, of course, entirely sensible: it cannot be seriously denied that it is of great consequence to obtain cells, even those with purported therapeutic potential, via the destruction of a human being. As hESC pioneer James Thomson famously put it: “If human embryonic stem cell research does not make you at least a little bit uncomfortable, you have not thought about it enough.”[4]

Recent events have provided an opportunity to consider the ramifications of that discomfort. The thoroughly discussed hesitancy of many Americans to receive COVID-19 vaccines (among others) given their links to abortion-derived cell lines[5] has brought into full focus the public health consequences of conducting research and developing therapies that put Americans in moral conflict. Speaking on this topic, NIH Director Dr. Jay Bhattacharya stated in his confirmation hearing that “we need to make sure the products of the science are ethically acceptable to everybody,”[6] subsequently noting that this is “not just an ethical issue, but it’s a public health issue.” We agree. But further, beyond merely being a public health issue, it foreshadows a public health crisis (or multiple) if we continue along the path of developing therapies that we know many of our citizens may not take.

It need not be so, for two reasons.

Firstly, the pragmatic reason: there is another way. Clinically, substantial impact has already been achieved by adult stem cells (ASCs),[7] to this day the only stem cell therapies with FDA approval. While these cells do not share the pluripotency of hESCs, this in fact contributes to their clinical translatability, as some of the challenges associated with hESCs trace to this very property.[8] The ethical acceptability and demonstrated successes of ASCs certainly merit further support as more such candidates[9] progress through trials. At the same time, the development of induced pluripotent stem cells (iPSCs) has provided an ethically acceptable cell source with the benefits of pluripotency, both for therapeutic candidates and for benchtop research. A recent clinical trial roundup has found iPSC and hESC candidates intermingled amongst a wide array of indications, with hESC trials tapering overall and iPSC trials expanding since 2019.[10] This trend is mirrored in the NIH’s data presented in this Request for Information, which shows federal support for iPSCs vastly outpacing that for hESCs in recent years.[11]

The reasons for this preference of iPSCs are multifaceted. There are scientific and clinical advantages, including the availability and diversity of cells, the availability of funding, and the ability to develop therapies that avoid the common hESC challenge of immune rejection.[12] But there are also, importantly, ethical reasons: echoing Director Bhattacharya’s remarks, researchers routinely reference the value of creating research outputs that are not ethically problematic.[13] In fact, the origin story of iPSCs attests specifically to these ethical considerations. Shinya Yamanaka, awarded the 2012 Nobel Prize in Physiology or Medicine for his work in developing iPSCs, has stated, “[w]hen I saw the embryo, I suddenly realized there was such a small difference between it and my daughters … I thought, we can’t keep destroying embryos for our research. There must be another way.”[14] And so he found one.

The presence of this “other way” casts new light on the historical discussions of hESCs and, in particular, the pressures regarding their public support. In an influential 2001 New York Times editorial, Stephen Jay Gould offered the following:

Speaking personally, I do not grant the status of a human life to a clump of cells in a dish, produced by fertilization in vitro and explicitly destined for discard by the free decision of the man and woman who contributed the components. But I also have no desire to offend the sensibilities of those who disagree. Thus, if I could derive cells of similar flexibility in a different way, I would gladly do so, even at considerable extra time and expense.[15]

We take profound issue with Gould’s characterization of the embryonic human, and we are not alone in that objection; indeed, biology itself testifies against the author.[16] Yet in this article, even the most strident public advancement of hESCs is provided with a caveat—that an alternative, if available, should be pursued instead, if not for the sake of the author, then for the sake of the many who disagree with him.

The presence of these alternatives, and their demonstrated uptake by the scientific and clinical communities, is certainly noteworthy in a discussion of the current status and future of stem cell research. Indeed, it fits squarely within the scope of this Request for Information insofar as this Request seeks public input on “emerging biotechnologies” that can “replace the use of hESCs.” Yet this Request additionally invites more input beyond alternatives, asking the scientific community to also justify its current (and future planned) use of hESCs. And here we encounter the second reason why we need not set ourselves on course for a future public health crisis: because it is necessary—and precedented—to set ethical limits on what science can do, even as it pursues noble ends.

While studies have indicated that some hESC researchers encounter moral discomfort in their work,[17] it is perhaps unsurprising given the dynamics of self-selection that many do not, even to the extent of associating ethics merely with “distracting controversies and poorly designed policies that impede scientific progress.”[18] But scientific progress is not a universal good to be pursued always, everywhere, and by any means; in fact, we already have restrictions in place recognizing this. In their discussion of the manifold breakdowns in public deliberations surrounding hESC research, J. Benjamin Hurlbut and Jason Scott Robert note:

…the observation that the policy environment has had a “chilling effect” on research is not sufficient grounds for criticizing funding limitations as such. Human subjects research protections have a definitive chilling effect on lots of forms of research; that is precisely their purpose. They are intended to prevent (well-intentioned) researchers from violating ethical norms that they may not themselves recognize or agree with.[19]

Across the history of hESC research communications, it is not uncommon to find mention of those ethical perspectives with which researchers disagree. But it is often the case that they are mentioned only to subsequently be ignored in practice, with the “ethical considerations” deemed pertinent to hESC work reduced simply to matters of informed consent, oversight, and appropriate “scientific justification.”[20] This latter phrase recalls the Warnock Report’s assertion that the embryo has a “special status” that affords him or her protection from being used “frivolously or unnecessarily” in research, but little more.[21] It is thus proposed that an adequate scientific rationale is sufficiently protective against abuses of this “high value” or “sensitive resource”[22] and, therefore, may signify to the public that the experiments proposed are reasonable—or, indeed, even ethically sound. Furthermore, as we have seen, the presentation of the scientific rationale for such studies—often taking the form of lofty promises of these cells’ potential—has subsequently dominated the public discussion, sustaining pressure to support and adopt these pursuits regardless of the ethical concerns about their means.

It is through this lens that we offer a cautionary remark on some of the likely responses to this Request for Information, as its call for hESC researchers to justify their work mirrors these long-standing trends in both academic and popular spheres. Surely, scientific rationales will be submitted in response to this Request describing why a particular research endeavor should use hESCs. But this alone is not sufficient. Again, Hurlbut and Robert provide keen insight:

Asking only about the (predicted) instrumental utility of research distracts from the deeper question of what makes for scientific projects that reflect the values, needs, and aspirations of the society in which they are undertaken. These are questions about science itself and about the social contract with science—about how society’s aspirations can and should be reflected in the forms of science it supports and upon which it relies.[23]

The questions at hand are indeed beyond mere scientific justification; instead, they ask to what extent—if at all—public support should be enmeshed with research that is objectionable to many Americans and whose fruits may well be on course to yield a public health crisis of our own making. Or, put alternatively, they propose an opportunity: what role can the policies of scientific funding play in establishing, developing, and making widely available that research which is, in the words of the NIH Director, “ethically acceptable to everybody”?

The reality is that science is a resilient field, one that operates within constraints as a matter of course. These constraints are not always technical in nature, nor are they always agreed upon by those whom they regulate. But that can be precisely why they are necessary. To achieve research outputs that do not place Americans in moral conflict, we must place guardrails on the research done by those who may not perceive such conflict. In doing so, we will not only advance the use of existing ethical alternatives, but we will also open wide the path for the development of novel technologies from which all can benefit in sound conscience.

Submitted on behalf of the Charlotte Lozier Institute.

Cameron Louttit, Ph.D.
Director of Life Sciences
Charlotte Lozier Institute
Arlington, VA 22206
202-223-8073

[1] Antonio Regalado, “After 25 Years of Hype, Embryonic Stem Cells Are Still Waiting for Their Moment,” MIT Technology Review, August 9, 2023, https://www.technologyreview.com/2023/08/09/1077580/embryonic-stem-cells-25-years-treatments/.

[2] J. Benjamin Hurlbut and Jason Scott Robert, “Stem Cells, Science, and Public Reasoning,” Journal of Policy Analysis and Management 31, no. 3 (2012): 707–14, https://doi.org/10.1002/pam.21611.

[3] Hurlbut and Robert, “Stem Cells, Science, and Public Reasoning.”

[4] Gina Kolata, “Man Who Helped Start Stem Cell War May End It,” The New York Times, November 22, 2007, https://www.nytimes.com/2007/11/22/science/22stem.html.

[5] Meredith Wadman, “Vaccines That Use Human Fetal Cells Draw Fire,” Science 368, no. 6496 (2020): 1170–71, https://doi.org/10.1126/science.368.6496.1170.

[6] Nomination of Jayanta Bhattacharya to serve as Director of the National Institutes of Health: Hearing before the U.S. Senate Committee on Health, Education, Labor & Pensions (2025), https://www.c-span.org/program/senate-committee/nih-director-nominee-testifies-at-confirmation-hearing/656402.

[7] David A. Prentice, “Adult Stem Cells: Successful Standard for Regenerative Medicine,” Circulation Research 124, no. 6 (2019): 837–39, https://doi.org/10.1161/CIRCRESAHA.118.313664.

[8] See Manon Desgres and Philippe Menasché, “Clinical Translation of Pluripotent Stem Cell Therapies: Challenges and Considerations,” Cell Stem Cell 25, no. 5 (2019): 594–606, https://doi.org/10.1016/j.stem.2019.10.001.

[9] See, e.g., Dragomirka Jovic et al., “A Brief Overview of Global Trends in MSC-Based Cell Therapy,” Stem Cell Reviews and Reports 18, no. 5 (2022): 1525–45, https://doi.org/10.1007/s12015-022-10369-1; Pingping Han et al., “Engineered Adult Stem Cells: Current Clinical Trials Status of Disease Treatment,” in Progress in Molecular Biology and Translational Science, vol. 199 (Elsevier, 2023), https://doi.org/10.1016/bs.pmbts.2023.02.007.

[10] Agnete Kirkeby et al., “Pluripotent Stem-Cell-Derived Therapies in Clinical Trial: A 2025 Update,” Cell Stem Cell 32, no. 1 (2025): 10–37, https://doi.org/10.1016/j.stem.2024.12.005.

[11] National Institutes of Health Office of Science Policy, “Supplemental Information for Guide Notice NOT-OD-26-031: NIH Pause on New Submissions to the NIH Human Embryonic Stem Cell Registry and Request for Information on Reducing Reliance on Human Embryonic Stem Cells in NIH-Supported Research,” https://osp.od.nih.gov/supplemental-information-for-guide-notice-pause-on-new-submissions-nih-human-embryonic-stem-cell-registry-and-rfi-on-reducing-reliance-on-human-embryonic/.

[12] Maureen L. Condic and Mahendra Rao, “Alternative Sources of Pluripotent Stem Cells: Ethical and Scientific Issues Revisited,” Stem Cells and Development 19, no. 8 (2010): 1121–29, https://doi.org/10.1089/scd.2009.0482.

[13] E.g., Samaneh Dehghan et al., “Human-Induced Pluripotent Stem Cells-Derived Retinal Pigmented Epithelium, a New Horizon for Cells-Based Therapies for Age-Related Macular Degeneration,” Stem Cell Research & Therapy 13, no. 1 (2022): 217, https://doi.org/10.1186/s13287-022-02894-0; Daniela Gois Beghini et al., “Induced Pluripotent Stem Cells: Hope in the Treatment of Diseases, Including Muscular Dystrophies,” International Journal of Molecular Sciences 21, no. 15 (2020): 5467, https://doi.org/10.3390/ijms21155467; David A. Yefroyev and Sha Jin, “Induced Pluripotent Stem Cells for Treatment of Alzheimer’s and Parkinson’s Diseases,” Biomedicines 10, no. 2 (2022): 208, https://doi.org/10.3390/biomedicines10020208; Condic and Rao, “Alternative Sources of Pluripotent Stem Cells.”

[14] Martin Fackler, “Risk Taking Is in His Genes,” Science, The New York Times, December 11, 2007, https://www.nytimes.com/2007/12/11/science/11prof.html.

[15] Stephen Jay Gould, “What Only the Embryo Knows,” The New York Times, August 27, 2001.

[16] Emile Scarpelli, “The Earliest Cells: Who Are They?,” The Journal of Maternal-Fetal & Neonatal Medicine 12, no. 4 (2002): 219–21, https://doi.org/10.1080/jmf.12.4.219.221.

[17] Steven P. Wainwright et al., “Ethical Boundary‐work in the Embryonic Stem Cell Laboratory,” Sociology of Health & Illness 28, no. 6 (2006): 732–48, https://doi.org/10.1111/j.1467-9566.2006.00539.x.

[18] Holly Longstaff et al., “Scientists’ Perspectives on the Ethical Issues of Stem Cell Research,” Stem Cell Reviews and Reports 5, no. 2 (2009): 89–95, https://doi.org/10.1007/s12015-009-9068-y.

[19] Hurlbut and Robert, “Stem Cells, Science, and Public Reasoning,” 709.

[20] See, e.g., Bernard Lo and Lindsay Parham, “Ethical Issues in Stem Cell Research,” Endocrine Reviews 30, no. 3 (2009): 204–13, https://doi.org/10.1210/er.2008-0031.

[21] Mary Warnock, Report of the Committee of Inquiry into Human Fertilisation and Embryology (London, 1984), 63–64, https://www.hfea.gov.uk/media/2608/warnock-report-of-the-committee-of-inquiry-into-human-fertilisation-and-embryology-1984.pdf.

[22] Erica C. Jonlin et al., “What Does ‘Appropriate Scientific Justification’ Mean for the Review of Human Pluripotent Stem Cell, Embryo, and Related Research?,” Stem Cell Reports 20, no. 5 (2025): 102479, https://doi.org/10.1016/j.stemcr.2025.102479.

[23] Hurlbut and Robert, “Stem Cells, Science, and Public Reasoning,” 710, citing Sheila Jasanoff, ed., Designs on Nature: Science and Democracy in Europe and the United States (Princeton University Press, 2007).