It has now become possible to make body parts in vitro. The production of life no longer has to occur by means of bodies, or through reproduction. But at the same time, this means that life takes on a new status: it finds itself divided up among mini-organs – organoids – cultivated in vitro that possess characteristics very similar to the real things. Brains, intestines, livers, and kidneys could soon be produced, in 3D and in vitro, that have the same structural, architectural, and, in part, functional characteristics as the organs of living beings; and they would be produced through a cellular proliferation and differentiation similar to what would have taken place in an embryo. A synthetic life, and a major scientific advance.
In order to create these organoids, human pluripotent stem cells are used which are then “directed,” through very specific conditions, towards a differentiation into various progenitive cellular lines, and finally into cells of the desired type. The genetic blueprint is the same as that of the original stem cell. In order to accomplish this, a 3D matrix is typically used that facilitates this type of development, one that is capable of being steered towards the desired structure. Works are also in progress in order to end up with the same results on the basis of human adult cells that are already differentiated and that can become pluripotent once again, as if time were reversed. Organs, or parts of organs, could then be recreated at any moment, regardless of how much time has passed, and regardless of the differentiations that have already taken place. One could recreate oneself at a distance, as it were. Would it be possible to go so far as to create detached human pieces, able to be substituted for those that have been subjected to the deleterious effects of time, or illnesses? Thanks to these new technologies, would it be possible one day to “remake” oneself, to give oneself a transplant, organ by organ, the minute it has succumbed to the pressures of age and use? A fragment of oneself, formed in vitro, and thus without any risk of rejection?
This is no easy task when it comes to the brain: cerebral organoids would have to reproduce the complexity of a structure that possesses different interdependent regions, and would have to mimic the development, in vitro, of what would have taken place in vivo. Up to now the organoids that have been made have been able to develop some hints of cerebral lobes, of specific cerebral regions, and to have a measurable electrical activity. But does this activity really correspond to thought, to sensation, to representation? It is obviously impossible to know.
For the moment, the idea is not that these cerebral organoids could be introduced into the brain: instead the goal is to make experimental models that would allow for the study of neuro-development, that could mimic certain anomalies, in order to better explore the mechanisms of certain neurological maladies using pluripotent stem cells that come directly from patients. They could also be used for the study of toxicological or infectious processes: to test medicines or the deleterious effects of certain toxins, particularly of infections. A study published recently has in fact successfully mimicked the effects on human cerebral organoids of being infected by the ZIKA virus, and has shown that this infection results in an increase of cell death, and a reduction of neuronal proliferation: proof of the link between the viral infection and the anomalous cerebral development that has been observed in foetuses. With this momentum, it is hoped that the basis of complex diseases such as autism or schizophrenia might be modeled in the near future.
Will any of this be used to develop new approaches to human reproduction? One can already imagine being able to produce a testicular organoid capable of spermatogenesis in vitro: thus, why not fertile spermatazoids as well?
However, the ability to make organs in vitro could also open up other perspectives. Human fantasies are fixated on biotechnologies. Two hundred years after Mary Shelley’s imagination created Victor Frankenstein – the modern Prometheus who was able to create life from death – these phantoms of our collective imagination are reappearing. Pedro Almodovar, in The Skin I Live In, took up this theme, making a synthetic skin for his own creature to wear. However, we must figure out how to detach ourselves from the obscurantism and catastrophic phantasmorgias according to which any step forward is also seen as a slippery slope in the direction of the terrifying.
 Lancaster et al., Nature, 2013.
 Qian, Cell, 2016.
 Lancaster et al., Science, 2014.
 One recalls Victor Frankenstein’s words: “I have succeded in finding the cause of the gerneation of life. I have even become capable of animating inert matter… Nothing would prevent me from animating matter,” Mary Shelley, Frankenstein, or the Modern Prometheus, chapter four.