The additional protocol to the Council of Europe Convention on Human Rights and Biomedicine, prohibiting the cloning of human beings, came into force on 1 March, having been ratified by the required five member states (Slovakia, Slovenia, Greece, Spain and Georgia). The protocol has also been signed by an additional 24 countries, including several EU countries but excluding the UK, which is also not a signatory to the original Convention itself. Interestingly, the protocol leaves it up to individual countries to define what is meant by a "human being". If embryos created by cell nuclear replacement for research into embryonic stem cells (and only allowed to develop for up to 14 days) are not defined as "human beings", then the recent changes to the UK Human Fertilisation and Embryology Act permitting this research would not necessarily prevent the UK from signing the protocol.