Scientists are calling for a ban on research aimed at creating "mirror life" after warning that bacteria built with an inverted chemical structure could evade natural immune systems.
Thirty-eight scientists have warned of an unprecedented risk to life on Earth.
Essential molecules in all known life on Earth share a specific orientation. Proteins are formed by amino acids of one orientation, while DNA and RNA use sugars with the opposite orientation. This property is known as chirality, meaning many biomolecules can only interact correctly with others that have the same configuration.
Creating mirror life involves building organisms using molecular components that are mirror images of those found in nature. The goal could provide information on the origin and limits of life, but it also presents one of the most difficult biological risk scenarios to anticipate.
Evading natural defenses
The concern focuses on the possibility of creating mirror bacteria that can reproduce. David Relman, a Stanford University professor of medicine, microbiology and immunology, said there was something for the first time that could threaten a large part of life on the planet.
Relman said scientists who have studied the possibility have not been able to prove that there is an obstacle making the creation of reproducing mirror bacteria impossible.
A mirror organism could behave very differently when faced with natural defense mechanisms. Human and animal immune systems have evolved over millions of years to recognize biological structures present in current organisms.
Researchers warned that a life form with an inverted chemistry could escape these recognition mechanisms. They said a similar situation could occur with plant defenses and the interactions that normally keep microbial populations under control.
Calls for international regulation
Relman and Stanford jurist Henry Greely said there is no reason to panic, but they believe there is a need to act in advance. They noted that biology is complex, and there are many unknowns about whether a mirror organism could survive, reproduce and compete effectively outside a laboratory.
More than 100 researchers met at the Institut Pasteur in Paris in November 2025 to analyse the feasibility and potential risks of mirror bacteria.
A group of scientists subsequently published a statement in the journal Science calling for a ban on research directed at creating the organisms. They warned that mirror organisms could evade numerous immune defenses in humans, animals and plants.
Establishing common rules to limit the research through an international body faces challenges. Researchers noted that reaching binding international agreements requires time, cooperation and effective oversight mechanisms, following precedents like the recommendations developed for human genome editing.
They added that achieving global consensus can be complicated in a context of distrust towards scientific institutions.
Creating a fully functional mirror life form remains beyond the reach of an individual researcher. Technical, economic and scientific obstacles mean it will likely be several years before the possibility can materialise.
Researchers said this margin of time provides an opportunity to anticipate risks before the technology is mature, allowing scientifically grounded limits to be established. They stated the goal is not to cause fear, but to use the available time to decide which life forms humanity should be able to create and which should be left out of reach.
