In a groundbreaking scientific development, researchers have created the world’s first lab-grown “synthetic embryos” which bypass the need of sperms, eggs, uterus, and even fertilization. A team of stem cell researchers led by molecular geneticist Joseph Hanna from the Weizmann Institute in Israel has created this medical marvel using stem cells from mice. It was found out that they could be self-assembled into early embryo-like structures with an intestinal tract, beginnings of a brain as well as a beating heart. The achievement was published in the journal Cell. Stem cells are cells that can develop into any organ or tissue. For this breakthrough, they were taken from mice and grown into an artificial womb for eight days where they developed all the aforementioned formations.

These embryos are called synthetic because they are created without any fertilized eggs. In the near term, this will potentially allow us to get a deeper understanding of how organs and tissues are formed and also, what takes place in the early stages of human pregnancy. Hence, the research could have major implications.

“This is a crucial stage: in humans, many pregnancies are lost around this stage, and we don’t really know why. Having models provides a way to better understand what can go wrong, and possibly insights into what we may be able to do about it,” stem cell researcher Megan Munsie, from the University of Melbourne, wrote in a piece for The Conversation.

However, most of the stem cells failed to form embryo-like structures. The embryo model could only survive 8 out of the 20-day mouse embryonic cycle, which is now considered a major disadvantage. Scientist Joseph Hanna, who led the research, said that the synthetic embryos were not “real” and did not have the potential to develop into live animals.

This drove some criticism. “It’s absolutely not necessary, so why would you do it?” Nicolas Rivron, a stem-cell scientist at the Institute of Molecular Biotechnology in Vienna, told MIT Technology Review in an interview. He further argued that scientists should only create “the minimal embryonic structure necessary” to yield cells of interest.

Dr James Briscoe, a principal group leader at the Francis Crick Institute in London, told The Guardian, “Synthetic human embryos are not an immediate prospect. We know less about human embryos than mouse embryos and the inefficiency of the mouse synthetic embryos suggests that translating the findings to human requires further development.”