Last week, Britain made a landmark decision that allows researchers to use animal eggs in the creation of human stem cells.
The ruling, laid down by the Human Fertilization and Embryology Authority, makes Britain the first country in the world to explicitly enable scientists to use human-animal hybrid embryos for research.
Hybrid embryos are banned in the United States, Australia, and Canada. Several countries in Europe, meanwhile, either allow scientists to only work on pre-existing embryos, or ban embryo research, altogether.
In an interview with ABC News, a spokeswoman from the HFEA said that the organization had carried out a detailed consultation with the public before its ruling.
"We found that, once people understood the science behind hybrid embryos, they changed their views," she said.
The plan involves taking an animal egg, usually from a cow or a rabbit, removing most of its own DNA content, and injecting human DNA into the empty animal egg. The resulting egg would then contain 13 animal genes compared with 20,000 to 25,000 human genes.
After scientists use a tiny jolt of electricity to encourage the egg to divide, it becomes an embryo in its earliest stages.
It is from such embryos that British scientists plan to extract stem cells — cells capable of developing into any human tissue.
Experts argue that using animal eggs filled with human DNA taken from a person suffering from a disease like Alzheimer's, for example, would allow them to study the resulting stem cells to see how the disease develops.
At present, researchers rely on a limited stock of human eggs left over from in vitro fertilization treatment. The HFEA ruling is expected to make it easier for scientists to conduct their research, without being dependent on a scarce supply of eggs.
Currently, two teams, from King's College London and Newcastle University, have applications pending with the HFEA, which has said that permission to develop hybrid embryos will be decided on a case-by-case basis.
Stephen Minger, leader of the King's College team, told ABC News that the HFEA ruling was "very good news for scientific research."
"We don't have thousands of young women coming into labs with embryos that we can use for research," he said, explaining why the new regulation was necessary.
If their proposal is approved, Minger's team intends to use the hybrid embryos to study the development of Alzheimer's, Parkinson's, and spinal muscular atrophy.
Their plan is to inject DNA, from patients suffering from these diseases, into empty animal eggs until they divide and form embryos. The resulting embryos will hold the patients' DNA, and enable Minger's team to understand the progression of the diseases.
As expected, the UK-based Alzheimer's Research Trust, and the Motor Neurone Disease Association, have welcomed the news of the HFEA ruling.
Rebecca Wood, chief executive of the Alzheimer's Research Trust, told ABC News that "stem cell research is an important part of Alzheimer's research."
Alluding to the "yuck factor" associated with the notion of human-animal hybrids in many people's minds, Wood insisted that such feelings "should not overrule the possibility of finding something" that may help evolve better treatments for Alzheimer's patients.