Revelations in recent months concerning the activities of the South Korean scientist Hwang Woo-Suk have again focused attention on the regulation of the use of human embryonic stem (ES) cells in medical research. Regulation of the use of human tissue in research and therapy has become increasingly topical in the European Union (EU).

The emphasis has moved from a focus on transplantation and the retention of organs for research to a consideration of the therapeutic use of tissues and the possibility of cloning. There has been much publicity about the potential of stem cells – a type of unspecialised cell that is capable of dividing and renewing itself for long periods, but which can give rise to differentiated cell types – and the ethical use of such cells and techniques.

On the one hand, we read of the possibility to clone individuals, and on the other, how an under-standing of these cells could give insights into medical conditions and be used to regenerate tissue or even whole organs. There are several sources of stem cells, but from a scientific perspective ES cells are particularly interesting since they are capable of differentiating into the greatest number of cell types.

Ultimately, Professor Hwang admitted that many of the results his group had published were in fact fabricated, but it is interesting to note that until recently, Korea did not have a regulatory regime, and it was the scientific community that raised the concerns about the origin of the embryos.

In the EU, there have been two initiatives regulating the use of human tissues and cells. Directive 2004/23/EC seeks to license and apply standards in the collection, processing and storage of cells and tissues for human use, while the European Commission recently proposed a draft regulation implementing a regulatory framework for the marketing of so-called advanced therapy medicinal products (COM(2005) 567 final). In each case, the framework only covers the use of stem cells in the course of medical treatment; regulation of research is currently left to member states.

Moreover, both initiatives seek to set minimum standards and the Directive in particular states that it "should not interfere with decisions made by member states concerning the use or non-use of any specific type of human cells, including… embryonic stem cells".

It is this final category that has generated huge diversity among member states as to what is permissible. Italy, for example, has banned any artificial creation and use of human embryos for purposes other than in-vitro fertilisation (IVF), while Germany only permits work on certain imported ES cell lines, but otherwise prohibits embryo research.

France recently completed the implementation of its Bioethics Act of 2004 by establishing a Biomedicines Agency whose authorisation will be required for the creation and use in France of human ES cell lines. Previously, only cell lines imported from other countries could be used under licence from the department of public health. Work is permitted using embryos remaining after IVF with consent from the egg donors where the research concerns incurable or particularly serious diseases. The regime does not permit the creation of embryos outside a programme of IVF nor any form of cloning or similar techniques.

The UK, meanwhile, has one of the most permissive regulatory frameworks in Europe. The Human Fertilisation and Embryology Authority (HFEA) was established in 1990 to oversee both fertility treatment and also research on human embryos. Under the Human Fertilisation and Embryology Act 1990, as updated in 2001, the HFEA can authorise the creation, storage and use of human embryos up to a certain age for research purposes where this is believed by the HFEA to be necessary and desirable for increasing and/or applying knowledge about serious disease.

The Act does not impose limits on how such embryos may be obtained and it was recently reported that the HFEA was proposing to allow the donation of eggs by women who were not at the same time receiving fertility treatment. It is also clear that the HFEA can license the creation of embryos specifically for research purposes.

The HFEA has furthermore authorised the creation of embryos for research purposes using the technique of cell nuclear replacement, sometimes called therapeutic cloning, which was made famous by Dolly the sheep. Therapeutic cloning entails the creation of embryos using donated eggs where the DNA from the nucleus of the egg is replaced with the DNA of another person and then caused to develop into an embryo. The resulting embryo is then used for research purposes. The legality of HFEA's authorisation to create such an embryo was upheld by the House of Lords in Regina (Quintavalle) v Secretary of State for Health [2003]. However, the implantation of such an embryo is illegal in France, Germany, Italy and the UK.

Scientific innovation in the field of stem cell research has provided a challenge to the law, which must balance the objectives of safeguarding public health, allowing proper consideration of ethical complexities and still promoting further innovation. Given that any decision taken in the field is driven by controversial ethical concerns, it seems unlikely that further harmonisation is possible. The result is likely to be that research, and perhaps even the benefits of such research, will concentrate in some parts of the EU at the expense of others.

George Pickering and John Wilkinson are members of the life sciences transactions group in the London office of Reed Smith.