Scientists create first human synthetic model embryos that may eliminate the need for eggs, sperm

Researchers say they have created the first synthetic human embryo-like structures from stem cells. (Representational)

Scientists in the United States and the United Kingdom have made a groundbreaking achievement by successfully generating synthetic human embryo-like structures using stem cells, eliminating the need for eggs and sperm.

Although these structures are in the earliest stages of human development and lack vital organs like a beating heart or a brain, they hold significant potential for advancing the understanding of genetic diseases and uncovering the causes of miscarriages.

However, this breakthrough raises crucial legal and ethical concerns since many countries, including the US, lack regulations governing the creation and handling of synthetic embryos. The rapid progress in this field and the increasing complexity of these models have sparked alarm among bioethics experts as they approach the boundaries of life.

James Briscoe, associate research director at the Francis Crick Institute, emphasized the need for regulations in this area, stating, "There is an urgent need for regulations to provide a framework for the creation and use of stem cell derived models of human embryos."

The research was presented by Dr. Magdalena Zernicka-Goetz at the International Society for Stem Cell Research's annual meeting in Boston. Zernicka-Goetz, a professor of biology and biological engineering at CalTech and the University of Cambridge, revealed that the study has been accepted by a respected scientific journal but has yet to be published. The initial report on this research came from The Guardian.

Previously, Zernicka-Goetz and her team, along with a competing team in Israel, had successfully created model embryo-like structures using mouse stem cells. These "embryoids" displayed early developments of the brain, heart, and intestinal tract after approximately eight days of growth.

The current embryo-like structures created by Zernicka-Goetz's team were grown from single human embryonic stem cells that were guided to differentiate into three distinct tissue layers.

These layers consist of cells that would normally form the yolk sac, placenta, and the embryo itself. These structures are the first to include germ cells that could eventually develop into eggs and sperm, she told CNN.

Zernicka-Goetz clarified that these embryo-like structures are not actual human embryos but rather models that closely resemble them. She highlighted the significance of these models, stating to CNN, "They are very exciting because they are very looking similar to human embryos and [are] a very important path towards the discovery of why so many pregnancies fail."

While these models mimic some features of natural embryos, they do not possess all of them. Researchers anticipate that studying these model embryos will provide valuable insights into the "black box" of human development, the period beyond 14 days after fertilization. This timeframe serves as the ethical limit for scientists to study embryos in a laboratory.

Currently, the synthetic human embryos remain confined to test tubes. Implanting them into a womb would be illegal, and previous attempts to implant similar synthetic embryos from mice and monkeys into animals have failed, likely due to the incomplete replication of pregnancy conditions.

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Zernicka-Goetz stressed that the objective of her research is not to create life but to prevent its loss by understanding why embryos sometimes fail to develop and implant after fertilization.