October 1, 2022


Scientists call them early stage hybrid embryos; the media calls them "Frankenbunnies". Whatever the name, they’re controversial: the nucleus of a human cell inserted into the emptied egg of a rabbit. It is an ethical barrier which has not been crossed before by mainstream Western scientists. But now three teams of British stem cell scientists have applied to create them to study diseases and create drugs. The regulatory body, the Human Fertilisation and Embryology Authority, has encouraged the application, so approval seems likely.

The scientists, who work in London, Edinburgh and Newcastle, insist that the resulting embryo will be 99.9% human and only 0.1% rabbit. The only rabbit genetic material will be what remains in the mitochondria. The entities — whatever they are — will be destroyed before they reach 14 days.

A scientist in Shanghai has already created dozens of rabbit-human hybrids and derived stem cells from them. Now that it has become clear that thousands of human eggs will be needed to create cloned embryos for research, scientists are looking for other sources. Rabbit eggs are abundant and cheap.

"If we learn how to do this with animal eggs, we should be able to have more success with human eggs, and I’d much rather know that if we were going to ask women to donate eggs that we were very likely to get stem cells as a result," said Chris Shaw, a neuroscientist who is collaborating with the London and Edinburgh teams. "We know this is a huge challenge after the downfall of Dr Hwang in South Korea, who failed to get stem cells despite having 2,000 human eggs."