The future is now — and it has a curly tail.
According to the Guardian, scientists at the University of California, Davis have successfully engineered a human-pig embryo that — had it been brought to term — would have resulted in an otherwise normal pig with a human pancreas.
Using CRISPR, what Mic writer Max Plenke once called "the Beyoncé of gene editing techniques," researchers essentially deactivated the pig's pancreas-producing DNA, injected the pig embryo with human stem cells and let it mature for 28 days before terminating it.
"You are basically creating a vacuum, a hole, so that the human cells respond to the right cues, they make a pancreas," Francis Crick Institute geneticist Robin Lovell-Badge explained to the Guardian. "The pig cells can't."
While scientists are hopeful about what the discovery could mean for transplants, there remains some concern that a human immune system would reject the pig-harvested organs.
Lovell-Badge continued, "There are other cells types that are going to be present in the pancreas which come from the pig – that would include blood vessels. Those would be a big problem and they would be rejected by a human."
Of course, questions of ethics typically arise when it comes to stem cell research. Despite the potential for cleaner, more readily available organs, animal rights activists worry about using animals as incubators. Peter Stevenson, a member of Compassion in World Farming, told the BBC, according to the Guardian, that he thinks it would "open up a new source of animal suffering."
But as the public continues to sort out moral quandaries, stem cell scientists will press on. When President Obama signed executive action lifting restrictions on the controversial research in 2009, he said, "I cannot guarantee that we will find the treatments and cures we seek. No president can promise that. But I can promise that we will seek them actively, responsibly and with the urgency required to make up for lost ground."