Human beings have long questioned the fundamental nature of life, the possibilities of controlling it, and the implications of doing so. Philip Ball’s new book, How to Grow a Human, presents a fresh perspective on these questions, using the example of ‘organoids’: organ-like structures derived from tissues like skin.

Last week, members of Bristows attended a meeting hosted by the innovation foundation, Nesta, at which the writer spoke about developments in organoid technology, and how his involvement in a research project had made him re-examine what it means to be human.

Ground-breaking innovation

Before addressing ethical and philosophical concerns, the author described one of the most important moments in modern genetics, when in 2006, a paper appeared in the journal Cell, by a former orthopaedic surgeon, Shinya Yamanaka. Yamanaka’s paper described a simple method for achieving something previously considered impossible: reversing the progressive specialisation (differentiation) of cells that takes place as they divide during embryonic development. Such IPS cells (induced pluripotent stem cells) are as capable of differentiating into any bodily tissue as cells in an early embryo. This reduces the demand for surplus human embryos, by making equivalent platforms more freely available to researchers. Without the need for human embryos, ethical objections seem to melt away. However, as Ball showed, they hardly disappear.

Using existing and emerging techniques, IPS cells can be artificially guided down chosen paths of development, thereby creating tissues resembling, sometimes closely, those in an adult human. Moreover, some differentiated tissues organise themselves into structures similar to organs such as livers and lungs: human ‘organoids’ that might reduce and improve upon, the use of animals in research: another ethical advantage. But Yamanaka’s technique can be used to do far more. It’s possible to create entire, healthy mice from skin cells. In principle if not in law, therefore, human beings could also be created. In avoiding one ethical minefield, Yamanaka’s discovery has entered another, sparking challenging questions of identity, and where to draw legal lines.

Philip Ball described how he had been affected by his participation in research into early-onset dementia. A small number of his skin cells were removed and turned into IPS cells. These were then differentiated into neuronal and glial brain tissue. As it organised itself, Ball had the opportunity to observe his ‘mini-brain’ growing to the size of a giant pea. It grew no bigger, simply because it lacked a blood supply. However, Ball referred to research that could resolve this limitation. By inducing the development of blood vessels within the organoid, or by transplanting organoids into livestock, where natural vascularisation may take place, future mini-brains need not be quite as ‘mini’ as they currently are. While doubting that they possess any mental state, and recognising the technology’s potential to advance ground-breaking treatments for cancer and dementia, for example, Ball regards the emerging vistas with unease.

While sceptical about transhumanist hype, Ball’s ‘mini-brain’ experience led him to question whether some might conclude that future brain organoids possess sentience, are capable of suffering, and should enjoy rights or special respect. Would it be ethical to grow them at all? Would a time come when an engineered brain would need legal guardian? Should the livestock we grow human organs in have special status?

It gets harder still. Organoids are far from the only instance of how emerging life sciences challenge us to look deep into who we are, and at the proper limits of our powers. Prompted by questions from the audience, Philip Ball went on to consider whether genome-editing techniques such as “CRISPR” might enable us to engineer babies’ appearance and mental attributes. Although the potential is often hyped, the dilemmas are real, and demand our attention. Organoid technology, CRISPR and other emerging life sciences techniques have set off a burst of real-life ethical problems that, Ball suggests, cannot be avoided. The time is approaching when we will have to design legislation to accommodate them responsibly.