Biological models of human embryos that can develop heartbeats, spinal cords and other distinctive features will be governed by a code of practice in Britain to ensure that researchers work on them responsibly.
Made from stem cells, they mimic, to a greater or less extent, the biological processes at work in real embryos. By growing them in the laboratory, scientists hope to learn more about how human embryos develop and respond to their environment, questions that would be impossible to answer with real embryos donated for research.
