The Real Reason Pig-Human Chimeras Make Ethicists Uncomfortable

I recently came across a story about a controversial new science project: growing human organs inside pigs, cows, and sheep. It works by first removing the gene that a pig needs to make the desired organ--say, a pancreas. Once the scientist has a pig embryo lacking that gene, he injects human stem cells into the embryo, hoping that the human stem cells will fill in the gaps and make a human pancreas. The ultimate goal is to transplant those organs into humans. The project is so controversial that the National Institutes of Health has refused to fund it. The researchers are relying on private donors. Critics of these experiments say they are too risky because there is no way of knowing where the human stem cells will go. Will they just become a pancreas? Or could they become a brain? And if they become a brain, will the pigs who house them have human consciousness? Scientists working on the project are fending off these critiques by proceeding slowly and with extreme caution. Right now, they are only letting the embryos develop for 28 days inside a pig's uterus before removing them to see whether the cells are differentiating the way they want. But they plan to continue changing their gene modification process until they can successfully get a human organ to grow inside a non-human animal. I think the real reason these experiments scare us is that they will force us to confront the question of what makes humans different from animals. Bioethicist Jason Robert, who was inter...
Source: Science - The Huffington Post - Category: Science Source Type: news