The cutting-edge method of growing clusters of cells that organize themselves into mini versions of human brains in the lab is gathering more and more attention. These “brain organoids,” made from stem cells, offer unparalleled insights into the human brain, which is notoriously difficult to study.

But some researchers are worried that a form of consciousness might arise in such mini-brains, which are sometimes transplanted into animals. They could at least be sentient to the extent of experiencing pain and suffering from being trapped. If this is true – and before we consider how likely it is – it is absolutely clear in my mind that we must exert a supreme level of caution when considering this issue.

Brain organoids are currently very simple compared to human brains and can’t be conscious in the same way. Due to a lack of blood supply, they do not reach sizes larger than around five or six millimeters. That said, they have been found to produce brain waves that are similar to those in premature babies. A study has showed they can also grow neural networks that respond to light.

There are also signs that such organoids can link up with other organs and receptors in animals. That means that they not only have a prospect of becoming sentient, they also have the potential to communicate with the external world, by collecting sensory information. Perhaps they can one day actually respond through sound devices or digital output.

As a cognitive neuroscientist, I am happy to conceive that an organoid maintained alive for a long time, with a constant supply of life-essential nutrients, could eventually become sentient and maybe even fully conscious.

Time to panic?

This isn’t the first time biological science has thrown up ethical questions. Gender reassignment shocked many in the past, but, whatever your beliefs and moral convictions, sex change narrowly concerns the individual undergoing the procedure, with limited or no biological impact on their entourage and descendants.

Genetic manipulation of embryos, in contrast, raised alert levels to hot red, given the very high likelihood of genetic modifications being heritable and potentially changing the genetic makeup of the population down the line. This is why successful operations of this kind conducted by Chinese scientist He Jianku raised very strong objections worldwide.