According to science.org, researchers are creating increasingly sophisticated brain organoids from human stem cells that can now form different brain regions and even connect into sensory pathways. At a conference last week at Asilomar Conference Grounds near Monterey, scientists, ethicists and patient advocates gathered to discuss the ethical implications of these advances, though they didn’t set new rules. Neuroscientist Sergiu Pasca’s team at Stanford has created neural assembloids that can detect stimuli and share information, while his work on Timothy syndrome has identified potential treatments using antisense oligonucleotides tested in rats with human organoid implants. The University of Pennsylvania’s Guo-Li Ming has used organoids to show how viruses like Zika and Oropouche damage brain development, explaining why infected mothers sometimes have babies with abnormally small heads. Patient advocates like Alison Singer of the Autism Science Foundation are pushing for faster progress, while bioethicist Ben Hurlbut of Arizona State University worries about experts setting standards without public input.
The consciousness question
Here’s the thing that keeps ethicists up at night: we’re creating increasingly complex brain-like structures, but we have no idea if they’re conscious. Pasca’s assembloids reacted to capsaicin – the chemical that makes chili peppers hot – which means they can detect noxious stimuli. But does that mean they feel pain? Probably not, since they lack the second pathway needed for the actual unpleasant sensation. Still, it’s getting uncomfortably close to creating something that might experience the world.
And then there’s the whole animal implantation issue. Pasca’s team put human brain organoids into rat brains to test potential treatments for Timothy syndrome. That’s medically promising, but it’s exactly the kind of human-animal boundary crossing that makes the public nervous. John Evans’ surveys show most people find this objectionable. But when you’re talking about treating fatal conditions, the medical need often outweighs the ick factor.
The treatment potential
Look, the medical applications are genuinely exciting. Timothy syndrome is a perfect example – it causes fatal heart arrhythmias along with autism and epilepsy, and there haven’t been good animal models to test treatments. Pasca’s team used patient stem cells to create both heart and neural organoids with the mutation, identified potential drug candidates, and tested them in rats with the human organoid implants. They’re planning to submit a clinical trial application early next year.
Basically, we’re looking at the first potential psychiatric treatment developed through brain organoid research. That’s huge for conditions that have been notoriously difficult to study. The technology is advancing so rapidly that even the researchers seem a bit surprised by how far they’ve come in just the past year.
Who gets to decide?
So who should be making the rules here? The Asilomar conference participants discussed whether existing bodies like the International Society for Stem Cell Research should provide guidance, or if we need a new organization entirely. But Ben Hurlbut’s criticism hits hard – he says these expert-led meetings typically result in standards being presented as a done deal to the public, shutting down real debate.
And he’s got a point. When you’re working with technology this fundamental to what makes us human, shouldn’t we have broader input? The researchers acknowledge public involvement is imperative, but the mechanisms for making that happen aren’t clear. We’re building increasingly sophisticated models of human brains, and the oversight framework feels like it’s playing catch-up.
The uncomfortable future
Where does this all lead? We’re not talking about full human brains in jars – these organoids are still just millimeters across. But they’re becoming more complex, forming connections, responding to stimuli. At what point does a collection of human neurons become something we need to treat differently? Evans says the big question is what we do next, and that’s not clear.
The technology is advancing whether we’re ready or not. Patients and families are counting on these breakthroughs, while ethicists worry we’re moving too fast. One thing’s certain: we can’t afford to wait until we’ve already crossed some ethical line we can’t uncross. The conversation has to happen now, before the science gets even further ahead of the ethics.
