In a world where advances in reproductive medicine and biotechnology move faster than laws and moral certainties, Dr. Heidi Mertes, Associate Professor of Medical Ethics at Ghent University, invites us to reflect on a question that challenges both science and conscience:
What value does an embryo have?
At the recent ESHRE Campus Workshop 2025, Dr. Mertes delivered a presentation that was both philosophical and urgent:
"Ethical considerations in choosing embryo research: exploring the moral status of embryos and newly-emerging embryo models."
Her session not only mapped out the current lines of ethical debate but also shed light—gently yet powerfully—on the gray areas surrounding embryos in scientific research.
Dr. Mertes identified three types of embryos used in research:
Embryos not suitable for transfer due to morphological or genetic abnormalities.
Supernumerary embryos—viable ones that are no longer needed due to the completion or abandonment of a parental project.
Embryos created specifically for research purposes.
This classification is not only technical—it’s deeply ethical. What rights does an embryo have if it will never be implanted? How does its "value" change depending on its origin or future?
Donating embryos to science can feel like choosing between two losses: discarding them or allowing them to contribute to research. Yet, as studies show, the emotional and symbolic weight patients attribute to their embryos varies significantly. For some, an embryo is just a cell. For others, it’s a child. And for many, something in between—a symbol of hope or a genetic link to the future.
Dr. Mertes also explored the rise of Embryo-Like Structures (ELS)—blastoids, gastruloids, and more. These new models offer the promise of scientific progress without using actual human embryos. But here lies the paradox:
The more these models resemble real embryos, the greater their scientific value—and the bigger the ethical challenge.
Dr. Mertes's message is clear: ethics must walk alongside science, not trail behind it. With voices like the ESHRE Ethics Committee weighing in, the current consensus is that integrated embryo models should not yet be granted the same moral status as natural embryos.
But if the science advances to the point where these models can undergo embryogenesis or result in live births in mammals, the recommendation is decisive: they should be subject to the same rules and ethical considerations as real embryos.
Moreover, existing natural embryos should always be prioritized for research, avoiding the creation of entities with equivalent moral status unless strictly necessary.
Rather than providing absolute answers, Dr. Mertes opens the space for necessary, thoughtful questioning. At the crossroads of laboratory and soul, what’s at stake is not only the future of fertility and regenerative medicine, but our very definition of life.