(Nature) – The United Kingdom has developed its first rules to guide research using human embryo models. Scientists say they are pleased the country has clarified its position on the fast-moving field.

The voluntary code of practice, published today, prohibits researchers from implanting embryo models made from human stem cells into the uterus of a living person or other animal. But it does not set fixed time limits on how long models can be grown in the laboratory, as some other countries have proposed. Instead, the code requires that projects propose their own limits on the basis of the minimum time needed to achieve their scientific objectives, and that an oversight committee be established to review and approve projects. (Read More)