The fictional Island of Dr. Moreau — a place imagined by H.G. Wells that harbors strange genetic human-animal hybrids — may soon become a reality. Researchers from University of California, Davis, have successfully injected human stem cells into pig embryos to produce human-pig embryos, known as chimeras, that can potentially grow into creatures that contain human organs, reports the BBC.

The goal of the research is not to create a pig-people, but rather to help solve the problem of a narrowing supply of transplant organs worldwide. Though of course, the research has whirled in controversy, garnering moral outrage by critics who fear that such genetic tampering could produce a pig that is eerily human-like.

So far the pig-human embryos have been allowed to gestate for just 28 days before the pregnancies are terminated and the tissue is removed for analysis. To be clear, the embryos are mostly of pig origin; only the genes of a specific organ — in this case, the pancreas — are human.

"Our hope is that this pig embryo will develop normally but the pancreas will be made almost exclusively out of human cells and could be compatible with a patient for transplantation," said Pablo Ross, a reproductive biologist who is leading the research.

The main concern is that the human cells might migrate to the developing pig's brain and make it, somehow, more human. But so far these fears have proven to be unfounded.

"We think there is very low potential for a human brain to grow, but this is something we will be investigating," said Ross.

The process works thanks to a breakthrough gene editing methodology based on Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR). Basically, a day-old pig embryo has the section of its DNA deleted that contains the instructions for building a pig pancreas. Human stem cells are then injected to fill the gap, thus providing alternative instructions to build a human pancreas instead.

Criticisms of the research aren't just based on fears of mad science. Animal rights activists question whether this might open up a whole new avenue for animal suffering — as incubators for human organs. There are real medical concerns for humans as well, for those who might receive one of these transplants. For instance, it could introduce pig viruses and diseases into the human population.

Researchers promise that all of these concerns are being thoroughly considered, however. One of the advantages of CRISPR is that it is particularly good at removing viruses too.

"Gene editing could ensure the organs are very clean, available on demand and healthy, so they could be superior to human donor organs," said professor George Church, a researcher at Harvard Medical School who, in other studies, has used CRISPR to remove more than 60 copies of a pig retrovirus.

In the end, patients on the long end of transplant waiting lists may simply need to ask themselves whether these fears outweigh the outcome they face if they run out of time without an adequate transplant.