Two teams of scientists have announced that they have grown embryo-like structures, made entirely from human stem cells, that are more advanced than any previous efforts. The synthetic embryos developed to a stage equivalent to that of natural embryos about 14 days after fertilization.
Such experiments could provide opportunities to study human embryonic development at later stages than ever before. But they also raise ethical and legal questions about the status of such ‘embryo models’ and how they should be regulated.
The work is described in two preprint studies1,2, posted to the bioRxiv server on 15 June by teams led by developmental biologist Magdalena Zernicka-Goetz at the University of Cambridge, UK, and stem-cell biologist Jacob Hanna at the Weizmann Institute of Science in Rehovot, Israel. Both groups had previously presented their findings at scientific meetings, with the work making headlines after Zernicka-Goetz spoke about her results at the annual meeting of the International Society for Stem Cell Research in Boston, Massachusetts, on 14 June.
Nature spoke to scientists about what these developments could mean for research...