Scientists Grew Human Cells in Monkey Embryos, and Yes, It's an Ethical Minefield

Few things in science freak people out more than human-animal hybrids. Named chimeras, after the mythical Greek creature that's an amalgam of different beasts, these part-human, part-animal embryos have come onto the scene to transform our understanding of what makes us "human." If theoretically grown to term, chimeras would be an endless resource for replacement […]