Researchers have created model embryos from mouse stem cells, complete with brains, beating hearts and the foundations of all the other organs of the body.
While the research was carried out using cells from mice, there are plans to use human cells, in the hope that this could guide the development of synthetic organs for patients awaiting transplants.
The research could also reveal why some embryos fail while others go on to develop into a healthy pregnancy.
"Our mouse embryo model not only develops a brain, but also a beating heart, all the components that go on to make up the body," said Magdalena Zernicka-Goetz, Professor in Mammalian Development and Stem Cell Biology at the University of Cambridge.
"It should also be possible to affect and heal adult organs by using the knowledge we have on how they are made," she added.
Little is known about how embryos develop, and creating a model embryo outside a womb - without using eggs or sperm - opens a new window on the process.
"This is an incredible step forward and took ten years of hard work of many of my team members. You never think your dreams will come true, but they have."
Prof Zernicka-Goetz, University of Cambridge
"This has been the dream of our community for years, and a major focus of our work for a decade and finally we've done it." Prof Zernicka-Goetz said. "It's just unbelievable that we’ve got this far."
The research focuses on an early phase when many pregnancies fail, at the point when three types of stem cells begin to send mechanical and chemical signals to each other, which tell the embryo how to develop properly.
Over the past decade, Prof Zernicka-Goetz’s group in Cambridge has been studying these earliest stages in order to understand why some pregnancies fail and some succeed.
"The stem cell embryo model is important because it gives us accessibility to the developing structure at a stage that is normally hidden from us, due to the implantation of the tiny embryo into the mother’s womb", she told Nature journal, in which the findings are published.
"This accessibility allows us to manipulate genes to understand their developmental roles in a model experimental system."
"This period of human life is so mysterious, so to be able to see how it happens in a dish – to have access to these individual stem cells, to understand why so many pregnancies fail and how we might be able to prevent that from happening – is quite special," said Prof Zernicka-Goetz.
Researchers say a big advance in the study is the ability to generate the entire brain which has been a major goal in the development of synthetic embryos.
