In the United Kingdom, the derivation of human embryonic stem (ES) cells falls under the 1990 Human Fertilisation and Embryology (HFE) Act and subsequent amendments that were adopted in 2001. These laws do not regulate research with ES cells, which follows specific national guidelines. Owing to rapid progress in science and to changes in legal and public opinion, the current British Government proposed further radical amendments in a new HFE Bill. These will have important consequences for research and clinical practice that involve both embryos and stem cells.