The creation of hybrid and chimaera embryos is a complex area and each avenue for research is associated with a different level of risk, benefit and ethical issues. It is difficult to generalise about the appropriate regulations that should be applied to the various ways to create embryos containing both human and animal material without considering the exact details of the proposed work, their corresponding benefits and potential uses. The Society's submission to the Select Committee inquiry briefly discusses the decision made by the Human Fertilisation and Embryology Authority (HFEA) in January 2007 not to grant licences to two research groups who wish to create embryos containing both human and animal genetic material without first undertaking a full public consultation on the issue. Stem cell research is still in its early stages and we believe that it is vital that progress in this area continues as it has the potential to limit or even end the suffering of people with conditions such as Alzheimer's, Parkinson's and motor neuron disease. Therefore it is essential that we do not close off avenues for development given the potential benefit of such work. The Society will comment on this issue in greater detail as part of our response to the forthcoming HFEA consultation.