Ethical concerns arise over synthetic human embryo

Scientists have created the first synthetic human embryos using stem cells rather than fusing egg and sperm, according to reports from the annual meeting of the International Society for Stem Cell Research. The embryos, which are only days or weeks old, could help researchers study the earliest stages of human development and explain the causes of pregnancy loss. The embryos are not identical to real embryos, but resemble them for the purposes of research. They are the work of Professor Magdalena Zernicka-Goetz and colleagues at the University of Cambridge and the California Institute of Technology. The synthetic embryos do not behave in the same way as real embryos and it is unclear how their use in research should be governed. The UK is drawing up voluntary guidelines for their use. Most countries currently use a 14-day rule on human embryo research. Synthetic embryos are not legally embryos and are not currently governed by the same rules. The embryos could provide an ethical alternative to the use of human embryos created through in-vitro fertilisation, but clear regulations and guidelines are needed. The synthetic embryos could be used to study the period of development in which many pregnancies are lost.