There’s something undeniably creepy about an animal that is partly human. And the more human it gets, the creepier it becomes. That is why the news that a Japanese team is well on its way to creating pigs with human organs has been described as something that will “ensure the employment of a generation of bioethicists”
That is probably an exaggeration. Bioethicists have already examined the problem of human-animal chimeras in depth. Even so, the new research suggests that they will need to be called back into action very soon.
Two years ago, the UK Academy of Medical Sciences released a groundbreaking report on “animals containing human material”. It concluded that most research on chimeras is permitted by existing UK laws. But it also identified some experiments that should not (yet) be done because of strong ethical objections. One is to breed an animal that has human sperm or eggs. Another is to create a non-human primate with a humanized brain.