Mixing animal and human material to create hybrids should be banned, says the Scottish Council on Human Bioethics. “”Most people are not aware that these kinds of experiments have been taking place in the UK and find it deeply offensive,” says Dr Calum MacKellar, the SCHB’s director of research. “Parliament should follow France and Germany and prohibit the creation of animal-human hybrid embryos.” However, the scientist who cloned Dolly robustly defended the use of hybrid embryos. “By casting a negative light on a number of important research opportunities, this report may limit medical progress,” says Dr Ian Wilmut.

Hybrids have been created in several experiments around the world over the past few years, but the SCBH questions their scientific merit. It warns that creating embryonic stem cells from the enucleated eggs of cows or rabbits filled with genetic material from a human cell poses “profound medical risks” and, in any case, would yield hard-to-interpret results.

Hybrids are far from fanciful, as they are a very practical solution proposed by some stem cell scientists who lament the shortage of human eggs for their research. In the UK, the government will probably propose new regulations on animal-human chimeras in October. And in Australia, the government is still agonising over whether to accept the recommendations of its Lockhart Review, which recommended legalising both therapeutic cloning and human-animal hybrids.