Scientists from the United States and the United Kingdom have paved the way for new research and insights in the field of human reproduction. They have successfully created synthetic human embryo-like structures without using eggs and sperm.
These structures represent the earliest stages of human development and hold immense potential for understanding birth defects, genetic diseases, causes of miscarriages and more.
However, the research also raises critical legal and ethical considerations, as no legislation governs lab-grown embryos.
But how similar are these structures to actual human embryos? Why is the study controversial? And will it really bring a shift in understanding human development? Let’s find out.
Synthetic human embryo-like structures
Teams of scientists led by developmental biologist Magdalena Zernicka-Goetz at the University of Cambridge, UK, and stem-cell biologist Jacob Hanna at the Weizmann Institute of Science in Rehovot, Israel, have made the breakthrough in human embryonic research.
They have grown embryo-like structures from human stem cells, which are more advanced than any previous research. The structures were developed to a stage similar to a natural embryo 14 days after fertilisation.
How similar are synthetic embryos to human embryos?
Synthetic human embryo-like structures are more like models of human embryos. They do not have beginnings of heart or brain development but exhibit three distinct tissue layers, including cells that can develop into the yolk sac, placenta and embryo itself.
What is the significance of these structures?
These embryo-like structures hold the potential to unravel the biological causes of recurrent miscarriages, a pressing concern affecting millions worldwide. They may shed light on what happens after fertilisation and before the embryo anchors to the womb, known as the ‘black box’ period of human development.
What happens during these 7 days, from the 14th day to the 28th day of human development, is unknown and crucial as during this period, primitive germ cells are formed, which grow to become eggs and sperm.
Current legal norms have a limit of 14 days to place an externally fertilised embryo in a woman’s womb. After which, scientists have only been able to study beyond the 28th day from an aborted foetus.
By studying synthetic embryos, they may unravel the mysteries of the black box period without relying on early embryos for research.
What motivated the research and development of synthetic embryos?
Propelled by the desire to unravel the mysteries of the black box period, teams led by Zernicka-Goetz and Jacob Hann worked to develop synthetic human embryos.
They had previously created model embryo-like structures using mouse stem cells, demonstrating the formation of key organs such as the brain, heart and intestinal tract within eight days. Building on this success, they successfully generated synthetic human embryos using individual human embryonic stem cells.
While synthetic embryos mimic human embryos, scientists may not be able to grow them into humans. Current legal restrictions confine synthetic human embryos to test tubes, preventing their implantation into a womb.
Previous attempts with stem cells from mice and monkeys have not survived, likely due to the incomplete replication of pregnancy conditions.
Furthermore, Dr Zernicka-Goetz clarified that the research’s objective is to understand the factors behind failed embryo development rather than creating life.
Why is synthetic embryo research controversial?
The legal restrictions and ethical considerations surrounding synthetic embryos make the research controversial. Unlike in vitro fertilisation (IVF), there is an absence of a clear regulatory framework for stem cell-derived embryo models.
The results from this study have stirred up discussions about the status of human embryos. It challenges the need for the 14-day limit and highlights the urgent need for guidelines and regulations to govern further advancements in these kinds of research.
What do experts say about this research?
While some experts are in awe of the research and understand its potential for understanding birth defects, genetic disorders, infertility and pregnancy complications, others are sceptical.
They feel it is essential to understand the difference between synthetic and natural embryos and the limitations the synthetic embryos carry. While they are similar, they may not replicate the natural process entirely.
These may be powerful models but are not actual embryos; How much to rely on such research is questionable.
Experts feel the need for thorough peer review and scientific scrutiny before concluding studies. They also stress the urgent need for guidelines to ensure the responsible and accountable use of this revolutionary technology.
