The competition to create embryoids, clusters of cells that resemble embryos, has generated controversy as several laboratories announce significant advances in the field. Embryoids are cell masses that mimic the functioning and development of an early embryo, but unlike real embryos, they do not require fertilization. Several teams of researchers have presented tentative studies using human material, raising ethical and legal concerns similar to those raised during cloning decades ago.
Although sometimes referred to as “synthetic embryos,” embryoids cannot develop into a viable fetus. These cell clusters are not completely synthetic, as they are generated from real cells. Scientists believe that embryoids are useful for understanding the first days of a human embryo, a stage that is not yet fully understood. Until now, experts used animal cells, mainly mice, for their experiments. However, the rivalry has now turned to human life.
Two leading research teams, led by Magdalena Zernicka-Goetz in the UK and Jacob Hanna in Israel, had already published scientific papers last year describing how they created the first mouse embryos. Recently, the Zernicka-Goetz team announced at a conference in Boston that they had succeeded in creating the first cell structures using human material. However, Hanna argues that these cell masses are not sufficiently developed and differentiated to be considered real embryos.
The lack of independent validation of these studies has raised doubts. The embryoid race has involved other research teams in China and the United States, but all of these studies have yet to be reviewed by independent scientists, a crucial process for academic validation. Some observers attribute the primacy of discovery to Hanna since, according to the provisional data published, his team did not have to genetically modify the human cells used, unlike the Zernicka-Goetz team.
The 14-day developmental period is crucial, as human embryos begin to form organs, including the brain, at that stage. However, very little is known about this period. Working with living organic material raises uncertainties about the legal status of these assays. It is necessary to proceed with caution and transparency to avoid mistakes or invalid announcements that could generate fear among the public and policymakers, warn experts in the field.