Eliminating Down Syndrome: Science or Eugenics?

March 10, 2025 
Author: Juan Manuel Palomares Cantero 
Versión en español

Science never ceases to amaze us. A team of Japanese researchers from Mie University School of Medicine and Fujita Health University has succeeded in eliminating the extra copy of chromosome 21 in human cells with trisomy 21. The discovery, published on February 18, 2025, in the journal PNAS Nexus, opens the possibility of "correcting" Down syndrome before a person is born. The procedure, led by Dr. Ryotaro Hashizume and his team, used a variant of the CRISPR-Cas9 tool to specifically identify and cut the third copy of chromosome 21 in induced pluripotent stem cells (iPSCs) derived from patients with Down syndrome. The results were promising: by eliminating the extra chromosome, the cells restored their normal chromosome number and showed improvements in viability and reduced cellular stress.

But if science advances, ethics should as well. Down syndrome is not a life-threatening disease like a lethal genetic mutation. Trisomy 21 has been, rather, a condition that society has learned to understand and value. So if we can "correct" its genetic origin, should we?

Supporters of this technique will argue that it is an opportunity to improve the quality of life for those who would be born with Down syndrome. But the procedure would only be viable in embryos created through in vitro fertilization, which would imply selecting those without trisomy or, in the future, modifying those that have it. The question is inevitable: are we curing or selecting?

This breakthrough would not allow for the "correction" of trisomy 21 in people who are already born. It is not possible to modify the DNA of all the cells of an individual without unpredictable consequences. For now, the only possible intervention is in embryos, which revives the specter of eugenics.

If we eliminate embryos with trisomy 21 because we consider their condition "undesirable," what comes next? Getting rid of those with a predisposition to chronic diseases? Modifying physical or cognitive traits to fit arbitrary standards of perfection? History has already shown us where the pursuit of "genetic purity" leads.

Bioethics demands caution. Technology may open fascinating doors, but it also raises dilemmas we cannot ignore. It is not just about eradicating a genetic condition but about deciding what kind of human diversity we are willing to accept. And perhaps, instead of modifying people to fit a predefined mold, we should ask ourselves whether the problem lies not in the condition itself but in the way society perceives it.

Juan Manuel Palomares Cantero es abogado, maestro y doctor en Bioética por la Universidad Anáhuac, México. Fue director de Capital Humano, director y coordinador general en la Facultad de Bioética. Actualmente se desempeña como investigador en la Dirección Académica de Formación Integral de la misma Universidad. Es miembro de la Academia Nacional Mexicana de Bioética y de la Federación Latinoamericana y del Caribe de Instituciones de Bioética. Este artículo fue asistido en su redacción por el uso de ChatGPT, una herramienta de inteligencia artificial desarrollada por OpenAI.

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