In the summer of 2026, two research teams—one at Cambridge University in the United Kingdom, the other at Columbia University in the United States—published studies that reignited the debate over editing the genes of human embryos. The technique, known as embryo gene editing, involves altering the DNA of an embryo for purposes that range from understanding early human development to preventing inherited diseases.
Both teams employed base editing, a method developed in 2016 that allows for more precise genetic modifications than the earlier CRISPR-Cas9 approach. Crucially, they conducted their experiments on human embryos rather than on mice, and their results drew international attention.
Embryo gene editing is not yet a clinical reality. The scientific challenges remain formidable, and no country currently permits modifications that would be passed on to future generations. But with these studies, the question arises: are we closer to safely creating gene-edited babies, and what ethical lines must be drawn?
What the studies found
The Cambridge team, led by Kathy Niakan, targeted a gene called NANOG, which proved essential for the formation of the embryo's body plan. Using base editing, they were able to inactivate the gene with far fewer unintended chromosomal errors than traditional CRISPR-Cas9. Niakan noted in a press release that base editing "represents a significant advance" because it carries a much lower risk of causing chromosome-level mistakes.
Across the Atlantic, Dieter Egli's group at Columbia used base editing on three genes: one linked to high cholesterol and cardiovascular disease, and two involved in haemoglobin production. Their goal was not to create edited babies but to learn how embryos repair damage in their genomes. Egli explained that this research could eventually lead to safer and more affordable IVF treatments by preventing genetic and developmental abnormalities.
Robin Lovell-Badge, a stem cell biologist at the Francis Crick Institute in London, told Euronews Next that the methods "look much safer" but that "there's still work to do." He pointed to mosaicism—where some cells are edited and others are not—as a persistent problem. "It looks like the levels of mosaicism are low, but not zero," he said, meaning that the risk of some cells escaping the edit remains.
The ethical minefield
Beyond the technical hurdles, the ethical questions are just as complex. Pascal Borry, professor of bioethics at the University of Leuven in Belgium, highlighted the tension between therapy and enhancement. "Where do we put the line? What is therapeutic? What is an improvement?" he asked. He also raised concerns about consent—embryos cannot consent—and about the potential stigmatisation of people already living with genetic conditions.
Borry further argued that embryo gene editing may not even be necessary. He pointed to pre-implantation genetic testing, a technique used during IVF to screen embryos for abnormalities before implantation. "There are many other alternatives to this technology," he said, urging reflection on whether such a powerful tool is needed when less invasive options exist.
Björn Heindryckx, a professor at Ghent University in Belgium, agreed that gene editing is not essential for preventing genetic diseases. However, he sees value in using it as a research tool. "If we can get more insight into embryo development, it will give us more insight into certain forms of infertility," he said.
Lovell-Badge took a more permissive stance. "I don't have a problem with doing it if it's safe and there's a good ethical reason," he said. He even suggested that in extreme scenarios—such as long-duration space travel where astronauts face high radiation—genetic modifications might be justified. He argued that countries should regulate the practice rather than impose outright bans.
As the science advances, the debate is likely to intensify. The European Union has no unified policy on embryo gene editing, leaving member states to set their own rules. Some, like Germany and France, have strict laws, while others, such as the UK, allow research under licence. The coming years will test whether Europe can find a common approach to this deeply personal and ethically charged technology.
