Opinion Express View on synthetic human embryos: All about life

Twenty years ago, actor Christopher Reeve gave a talk at the Yale School of Medicine, where he made an impassioned plea to those opposing embryonic stem cell research on ethical grounds. Reeve, who had lost the use of his limbs in an accident had become an ardent supporter of the relatively new field of study, which he believed had the potential to cure his condition. He died in 2004, too early to see the advances in stem cell research. One groundbreaking leap was announced at the International Society of Stem Cell Research’s annual meeting in Boston on Wednesday. Magdalena Zernicka-Goetz, who holds professorial chairs at the University of Cambridge and Caltech in the US, announced that her team has succeeded in creating synthetic human embryos using stem cells, sidestepping the need for egg and sperm.

Zernicka-Goetz said that the primitive embryos do not have a heart or a rudimentary brain but include cells that go on to form the placenta, the yolk-sac and the embryo itself. She hopes the research will shine a light on the “black box of human development”, the period before a pregnancy’s progress can be detected on a scan. The stem cell-based models could provide a window to understanding cases of miscarriage and help study genetic disorders without having to use early embryos.

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It’s not yet clear whether these embryos have the potential to progress beyond the early stage. But last year Zernicka-Goetz’s team demonstrated that stem cells from mice could be programmed into developing a beating heart and primordial brain. In a field of research that has been dogged by ethical concerns related to issues such as cloning, the new development will pose regulatory challenges. None of the animal embryos have gone on to produce living species. Even then, ethicists believe that this is the time to set boundaries — limit research to welfare such as alleviating the trauma of patients like Reeve.