Human cells grown in monkey embryos reignite ethics debate

Scientists confirm they have produced chimera' embryos from long-tailed macaques and humans

Monkey embryos containing human cells have been produced in a laboratory, a study has confirmed, spurring fresh debate into the ethics of such experiments.

The embryos are known as chimeras, organisms whose cells come from two or more individuals", and in this case, different species: a long-tailed macaque and a human.