Dutch scientists have built "synthetic" embryos in their laboratory using mouse cells other than sperm and eggs.

The stem cell breakthrough, described in Nature journal, is not for cloning people or animals, but about understanding why many pregnancies fail at an early stage - implantation.

The embryos, made in a dish, attached to the womb lining of live female mice and grew for a few days.
http://www.bbc.com/news/health-43960363