For the first time, researchers have successfully grown human cells inside early-stage pig embryos in the lab, creating pig-human hybrids, which the researchers describe as interspecies chimeras.
While still early days, the experiment might one day lead to lab-grown human organs that can be transplanted into those who need them, potentially saving thousands of lives. This type of research brings up a bunch of safety and ethical concerns.
A significant objection is the opportunity for viruses to more easily jump a species barrier which was previously closed to them. There is also the ‘ick’ factor of such an intimate mixing of human and animal tissues for medical reasons, as well as the concern that these hybrid pigs could develop more human brains.
“The idea of having an animal being born composing of human cells creates some feelings that need to be addressed,” Izpisua Belmonte told Hannah Devlin at The Guardian. The hybrid embryos in this experiment were terminated after 28 days of development (the first trimester for pigs) to avoid further ethical concerns.
No one really has any answers for these hypothetical questions, which is partly what makes the research seem so scary. In fact, the National Institutes of Health (NIH) has previously issued a moratorium on human chimera research, which they say they are in the process of lifting.