Bioethics in the Age of Organoids and Synthetic Embryos

Organoids are miniature, 3D structures derived from stem cells that mimic the structure and function of real organs. Synthetic embryos (embryo-like structures or embryoids), also stem-cell-derived, are more recent lab-created structures that resemble early-stage embryos without originating from a fertilized egg.1

Both models advance research by facilitating biomedical studies and expanding the scope of experimentation while addressing certain limitations of conventional approaches.1

Organoids and synthetic embryos represent major developments in medicine and science but also raise substantial bioethical concerns.

They provoke critical questions about the limits of scientific manipulation: Are these advancements ethically justifiable for medical progress, or do they overstep boundaries in manipulating life for scientific purposes?

In biomedical research, animal models and 2D human cell cultures have traditionally been essential. However, they fail to replicate the complexity of 3D tissue structures, limiting their ability to mimic in vivo conditions accurately.2

Moreover, the inaccessibility and limited availability of human tissue for research, combined with the challenges in translating findings from animals to humans due to genetic and morphological differences, highlight the growing need for advanced multi-cellular models.2-4

Organoids replicate the 3D architecture of human organs, offering insights into disease mechanisms and therapies. They have wide applications in genomics, cancer research, targeted treatments, and regenerative medicine, serving as a more accessible, cost-effective alternative to traditional models.3

Synthetic embryos mimic early human development, offering insights into embryogenesis, genetic disorders, and fertility, as well as the potential for disease modeling and drug discovery.2

Despite their promise, organoids and synthetic embryos raise complex ethical and moral questions requiring careful oversight.

The use of human stem cells, especially embryonic, raises concerns about sourcing and the ethics of using human tissue in research. Further problems arise over when to discontinue studies, particularly if these entities start developing complex or human-like properties.3,4

Cell donors must provide explicit, informed consent. However, the complexity of biomedical research makes it difficult to ensure donors fully understand the implications of cell donation, including potential uses in therapy, research, or other applications. Ethical issues also surround biobanks, especially data privacy, donor rights, and the unclear legal status of stored tissue.3,5

Organoids, capable of replicating various bodily organs, raise several ethical dilemmas. For example, brain organoids, which may exhibit human-like responses, raise concerns about potential sentience and the need for ethical protections.

Similarly, gonadal organoids challenge traditional reproductive concepts, requiring explicit consent and strict ethical guidelines to prevent exploitation.3

Manipulating human-like tissues prompts ethical scrutiny regarding potential misuse, including genetic modifications for non-medical purposes, as well as broader concerns related to genome editing and equity. In organoid transplantation, first-in-human trials present additional ethical challenges, including patient vulnerability, informed consent, and the risk of therapeutic misconception.3,5

The resemblance of synthetic embryos to natural ones in early development raises complex legal and moral questions about their status and personhood. Their potential classification as forms of human cloning further challenges established reproductive frameworks.

These advancements could profoundly influence societal conceptions of life, identity, and reproduction.3

Rapid advances in biomedical research have strained global regulatory frameworks. National policies vary: some enforce strict limits or outright bans, while others operate in ambiguous regulatory spaces, reflecting diverse ethical, legal, and scientific perspectives.4,6,7

In the US, the Food and Drug Administration (FDA) oversees organoid drug testing, while the National Institutes of Health (NIH) provides stem cell research ethics guidelines. In the EU, the European Medicines Agency (EMA) and national regulators oversee organoid-based research in drug development and transplantation, with embryo research regulations varying by country.8

In the UK, the Human Tissue Authority (HTA) and Human Fertilisation and Embryology Authority (HFEA) regulate research involving human tissues and stem cells.9

Stem cell regulations broadly cover organoids and face relatively fewer restrictions. In contrast, embryonic research is subject to stricter and more complex rules, often involving rigid limits on developmental stages and funding. However, because synthetic embryos do not currently fall under clear legal definitions, they may exist in a regulatory gray area.6,7

Many leading research countries enforce a '14-day rule' limiting human embryo culturing beyond two weeks (e.g., Australia, Canada), while others impose stricter limits, such as a 7-day limit (e.g., Switzerland), or have restrictive policies (e.g., Japan, South Korea). Some even ban embryo research entirely (e.g., Germany, Italy).6,7

In the US, embryonic research falls under a complex regulatory framework. Federal restrictions apply only to federally funded research, and no nationwide 14-day limit exists. Certain states impose broad prohibitions regardless of funding source.6

As developmental biology continues to evolve, global regulatory frameworks must adapt and remain flexible to accommodate emerging changes. International consensus is also essential to prevent fragmented oversight. Collaboration and standardized ethical guidelines will be key to unified governance and responsible regulation, ensuring their ethical and widespread adoption.7

Future governance should establish clear legal standards that balance scientific innovation with ethical considerations, safety, and societal values.

A multidisciplinary approach, involving bioethicists, regulatory bodies, scientists, policymakers, as well as members of the public will be essential for guiding the responsible development and application of these technologies.4

The rapid evolution of developmental biology offers great promise for medical innovation. However, it has outpaced existing legal frameworks, creating regulatory uncertainty and complex bioethical challenges.

Balancing potential with ethical integrity is crucial to ensure that organoid and synthetic embryo research benefits humanity without overstepping moral boundaries.

Clear regulations and strong ethical guidelines, shaped by global efforts, will be key to their safe, equitable, and ethical integration into healthcare.

Kim, Y., Kim, I., & Shin, K. (2023). A new era of stem cell and developmental biology: from blastoids to synthetic embryos and beyond. Experimental & Molecular Medicine, 55:2127-2137. doi: 10.1038/s12276-023-01097-8

Rosner, M., Reithofer, M., Fink, D., & Hengstschläger, M. (2021). Human Embryo Models and Drug Discovery. International Journal of Molecular Sciences, 22(2):637. doi: 10.3390/ijms22020637

Mollaki, V. (2021). Ethical Challenges in Organoid Use. BioTech, 10(3):12. doi: 10.3390/biotech10030012

Iltis, A.S., Koster, G., Reeves, E., & Matthews, K.R.W. (2023). Ethical, legal, regulatory, and policy issues concerning embryoids: a systematic review of the literature. Stem Cell Research & Therapy, 14, 209. doi: 10.1186/s13287-023-03448-8

Isasi, R., Bentzen, H.B., Fabbri, M., Fuhr, A., Glover, J.C., Mah, N., Mascalzoni, D., Mueller, S., Seltmann, S., & Kurtz, A. (2024). Dynamic governance: A new era for consent for stem cell research. Stem Cell Reports, 19(9):1233-1241. doi: 10.1016/j.stemcr.2024.07.006.

Matthews, K.R.W., & Moralí, D. (2020). National Human Embryo and Embryoid Research Policies: A Survey of 22 Top Research-Intensive Countries. Regenerative Medicine, 15(7):1905–1917. doi: 10.2217/rme-2019-0138

Oh, S., & Kim, E.Y. (2024). Organoid Global Regulatory Policy: A Cross-Sectional Study. The Pharmaceutical Society of Korea, 3(2):169-176. doi: 10.58502/DTT.23.0033

Song, S.J., Nam, Y., Rim, Y.A. Ju, J.H., & Sohn, Y. (2024). Comparative analysis of regulations and studies on stem cell therapies: focusing on induced pluripotent stem cell (iPSC)-based treatments. Stem Cell Research & Therapy, 15, 447. doi: 10.1186/s13287-024-04065-9

Human Tissue Authority (HTA). (n.d.). Regulating human embryonic stem cell lines for human application. [Online]. Available at: https://www.hta.gov.uk/guidance-professionals/regulated-sectors/human-application/regulating-human-embryonic-stem-cell (Accessed on 4 April 2025)

Last Updated: Apr 23, 2025