Recreating the earliest stages of life

In their effort to understand the very earliest stages of life and how they can go wrong, scientists are confronted with ethical issues surrounding the use of human embryos. The use of animal embryos is also subject to restrictions ...

Researchers generate human-monkey chimeric embryos

Investigators in China and the United States have injected human stem cells into primate embryos and were able to grow chimeric embryos for a significant period of timeā€”up to 20 days. The research, despite its ethical concerns, ...