Danger in the mirror

At the end of 2024 an international group of scientists issued a warning to the world: that the development of a ‘mirror organism’ – built from mirror-image versions of naturally occurring biomolecules – represented an existential risk to humanity[1]Katarzyna P. Adamala et al. ,Confronting risks of mirror life.Science 386,1351-1353(2024). A year on from the publication of that warning, and a technical report on the intentional and unintentional pathways that could lead us to disaster[2]Technical Report on Mirror Bacteria: Feasibility and Risks. , The Biologist and the RSB have been exploring what has been done so far by the scientific community to reduce the likelihood of a mirror-biology nightmare.

‘Mirror life’ is a concept based on the natural chirality of molecules found in the living world. Many chemicals can come in two mirror-image forms, or enantiomers, often described as left-handed or right-handed (see 'Mirrored Molecules' box, below). At the dawn of evolutionary time life began working in a certain chirality and has stuck with it: while biochemicals such as proteins, sugars, lipids and nucleic acids can physically exist in two mirror-image configurations, living organisms overwhelmingly use only one of them.

Theoretically, an exact mirror image of a given protein (made up of enantiomers of amino acids found naturally) will bind equally well to the mirror version of the small molecule to which it normally binds. Likewise, other mirror biomolecules should function normally as long as all the other molecules they interact with are all mirror molecules too. Replacing every single molecule in a cell with its enantiomer would in theory result in a ‘mirror cell’ that behaves identically to a naturally occurring cell.

The result could be unstoppable infections and irreversible ecological harm

However, as scientists have warned, developing such a cell – a mirror bacterium, for example – could have terrifying consequences. The Technical Report on Mirror Bacteria: Feasibility and Risks suggested that mirror bacteria might be less visible to human, animal and plant immune systems, both innate and adaptive, and more easily able to pass through barrier surfaces into the bloodstream. They might be resistant to existing antibiotics or antimicrobial toxins, and unrecognisable to bacteria killers such as phages and protists, meaning they outcompete naturally occurring cells. And almost all biocontainment procedures are imperfect. The result could be unstoppable infections in people, plants and animals around the world, and irreversible ecological harm[2]. Some have gone as far to say that unleashing mirror cells into the biosphere could “end all life on Earth”[3]'Mirror Microbes Could End All Life on Earth. How Do We Stop Them?' The Scientist, Sept 9 2025. .

With the report concluding that mirror bacteria “should not be developed”, the questions now being asked are whether the scientific community is doing enough to ensure that mirror life is not created – either intentionally or unintentionally – and what steps should be put in place to ensure that seemingly unrelated research does not open the door to those with malicious intentions. 

Pathways to problems

Researchers have been considering the dangers of mirror life since 1992. Then, a group of scientists writing in Science warned such organisms “would have built-in immunity to attack from normal life” and that “the synthesisers of life” need to “consider these matters in detail before getting started”.

Yet the creation of complex mirror biological systems and even entire mirror cells has been seen as an interesting scientific challenge by major funding bodies across the world. As recently as 2019 the US National Science Foundation awarded $4m to a group of investigators seeking “to design, construct and safely deploy synthetic mirror cells in which all of the key molecules … exist in chiral states opposite to their natural forms”. The National Natural Science Foundation of China has supported work to create a “mirror-image central dogma”, and the European Commission funded the ERA-Net MirrorBio consortium, which had similar goals.

Even as these projects have been scaled back or abandoned, advances in synthetic chemistry have permitted the creation of progressively larger mirror nucleic acids and proteins. One of the main goals of creating such molecules is the production of therapeutics with desirable functions that are not recognised and degraded by the body because of their chirality. This means that mirror peptides, for example, might last longer in the body and be less likely to evoke an unwanted immune response.

Mirror proteins have also been developed to aid experiments in determining protein structure. The development of mirror nucleic acids, and mirror versions of the enzymes involved in the synthesis of gene products, has meant the creation of mirror biomolecules is far less cumbersome than it once was. And as synthetic biology builds on its efforts to create simple living cells from the ‘bottom-up’ assembly of non-living components, the creation of mirror biological systems has become increasingly feasible. Based on current trajectories, the creation of mirror life is thought to be between 10 and 30 years away[2].

Stopping mirror life

The co-authors of the public warning, some of whom have previously worked on creating mirror life before deciding against it, do not believe any researchers are now actively pursuing the creation of mirror bacteria. In addition to their technical report, they are now convening meetings via the Mirror Biology Dialogues Fund to further evaluate the risks of mirror bacteria and explore steps that can be taken to minimise them.

Meetings or talks on the risks of mirror organisms have also been held by the Institut Pasteur; the US National Academies of Science, Engineering, and Medicine; the University of Manchester; and the RSB. Several funders in the US have confirmed they will not fund research aimed at creating mirror life, or have made it clear that the synthetic biology work they fund should avoid enabling the creation of mirror life[4]'Why We Won’t Fund Research Towards the Creation of Mirror Organisms.' Renaissance Philanthropy. Nov 18 2025. . (The UKRI has simply added research on mirror biology as a topic in its latest guidance on research with “potential misuse risk”[5]'Statement on research with potential misuse risk'. UKRI, 16 Oct 2025. .)

Other scientific committees and organisations have issued statements on the risks of mirror life and an entreaty was signed at the 2025 Spirit of Asilomar and the Future of Biotechnology conference stating that “mirror life should not be created unless future research convincingly demonstrates that it would not pose severe risks”. UNESCO’s International Bioethics Committee went further in recommending a precautionary global moratorium.

Dr Paul-Enguerrand Fady, a biosecurity expert at the Centre for Long-Term Resilience, says he has been disappointed that there hasn’t been an immediate moratorium put in place by major scientific bodies yet. “People have said we must be careful not to cast too wide a net and stop research that could be valuable. I appreciate that, but I think the wording we have suggested is completely uncontroversial as a starting point: don’t do research that will directly lead to the creation of mirror life. Other red lines, on what research could lead to the creation of mirror life, are much more difficult to draw, but not doing research that specifically aims to create it seems to me a simple ask,” he explains.

Fady says opinion differs on what research around mirror biochemistry is acceptable, with more safety-conscious views in the biosecurity and biorisk space, but concerns in the biomedical and biotechnology sectors that important innovation and new technologies will be stifled. The development of a ‘mirror ribosome’, for example, is a key technical accomplishment that could accelerate the creation of mirror life.

“Do we want people to be making mirror ribosomes? I would say no, but others would say it would simplify biomanufacturing of opposite-chirality biomolecules, which could be done cell free,” says Fady. “I could accept that, assuming that it’s contingent on never then taking the next step of putting it into a living organism or synthetic cell.”

2026 is hopefully the year [scientists] start to examine whether the potential benefits of mirror biology are worth the potential harms

Gathering real data

With no sign of a moratorium on direct mirror life research for now, organisations such as the Centre for Long-Term Resilience are trying to generate real data where concerns are currently speculative or hypothetical – for example, on the question of whether antibiotics would work on mirror bacteria and whether our immune systems would recognise them. Initial computational simulations[6]Fady, PE & Ciccone, JL. Simulations suggest that antibiotics would not work on mirror bacterial targets.The Centre for Long Term Resilience. Nov 28 2025. suggest few existing antibiotics would be effective against a mirror bacterium, but the evidence that the microbes could evade our immune defences is less certain. (As some researchers have pointed out, glycans – fundamental to the immune system’s recognition of ‘self’ and ‘non-self’ – exist in varying chiralities across species and taxa[1].)

“We think that is the next big thing scientists should be checking,” says Fady. “Is it true that the immune system wouldn’t detect the mirror bacteria? It shouldn’t be hard to check with access to a wet lab and funding.”

The centre has drawn up a list of questions, supported by grants, which Fady hopes “would really de-bottleneck a lot of the conversation by putting an evidence base where there isn’t one, so we can say the risk is, or isn’t, as high as we thought”. (The proposed experiments are of low dual-use risk – that is, they do not require the development of technologies that would in themselves further progress towards the creation of mirror life.)

Other policy research organisations, such as RAND, have been making assessments of the various milestones and developments in parallel or peripheral technologies that might inadvertently abet the creation of mirror life. The organisation has also been forecasting different cultural scenarios – from the diffusion of synthetic biology technologies throughout society to global political tensions driving the development of a new biological weapon – which it is using to stress test existing mechanisms of oversight and to prompt new policy ideas. These so far range from international frameworks to distinguish mirror biomolecule research from mirror organism research, to banning mirror cells through the Biological Weapons Convention.

The need for clarity

Sana Zakaria, senior research leader for science and emerging tech at RAND Europe, has been involved in the institute’s various discussions with policymakers, funders and research experts. “What’s really interesting is that the scientific community and the policy-government community are very much in the mode of self-regulation and initially many feel that may be sufficient. But when you explain these scenarios, which actually are not far-fetched, so could come to pass and will eventually come to pass, their reaction is very different. A lot of the experts felt that our current instruments are not sufficient,” she says.

Like Fady, Zakaria thinks more could be done by the scientific community to mitigate the risk of major milestones being hit or mirror life research continuing covertly.

“What really jumps out is that many stakeholders feel like it’s too early. But what are the signs it’s too early? We should actively identify what trade-offs and acceptable levels of risk we as a society are willing to take on, when we need to be in policymaking mode or intervention mode. It’s about having clarity around the signs we should be looking out for and accountability around whose responsibility it is to look out for them.”

If 2025 was the year that the potential risks of mirror life were bought to global attention, then 2026 is hopefully the year the scientific community starts to examine in detail whether the potential benefits of mirror biology are worth the potential harms and where governance can be bolstered.

“We have the luxury of time, for now, but we should be proactively working on these things now before we have to go into reactive mode,” says Zakaria. “We have seen in other areas of technology that have dual use – such as engineering biology and AI – that we’re now playing catch-up, and developments such as synthetic embryos have caught us completely off guard.”

An international event at the National University of Singapore in autumn 2026 aims to capture ongoing discussions and the latest research on mirror biology. Both the Royal Society of Biology and The Biologist will be keeping a close eye on its outcomes.

Tom Ireland is editor of The Biologist

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