Hybrid embryos are made by combining an animal egg and a human cell. They are used to overcome the shortage in human eggs available for research.
In May 2008 the UK Government passed a law allowing the use of hybrid embryos in research. They can be used to produce embryonic stem cells to study cell reprogramming and development. They can help us research treatment for diseases such as Parkinson’s. It is hoped that in the future this work will lead to new sources of embryonic stem cells and therapies for major diseases.
Why do this?
To study stem cells, scientists need to have access to enough of them. But this has been difficult because most have been harvested from donated human embryos. The embryos are destroyed in the process. Some people object to this, there have been legal barriers and a shortage of donors. Hybrid embryos offer a method to create new stem cells for research without needing to use donor embryos.
Why is this technology controversial?
The use of these hybrid or admix embryos has appalled some people and excited others. Some see this technique as crossing the boundary between humans and animals, creating embryos that are no longer fully human. Members of different faiths have condemned the technology on moral grounds. However, a survey of members of the public by the Human Fertility and Embryology Authority (HFEA) showed that, when the technology and its potential benefits were described to them, 61% were in favour of it.
BBC Religion and Ethics article on Human Animal Hybrids
The creation and uses of hybrid embryos