Scientists at the Weizmann Institute of Science in Israel have achieved a significant breakthrough by successfully growing a model of a functioning human embryo without the use of egg, sperm, or a womb.
This remarkable feat was accomplished by culturing stem cells in a lab, resulting in the development of human embryos with all the expected characteristics of embryos at 14 days. The embryos were even able to produce pregnancy hormones, leading to positive results in pregnancy tests.
The researchers used naive-state stem cells that were made to become into specific types of body tissue, including epiblast cells (fetus), hypoblast cells (yolk sac), trophoblast cells (placenta), and extraembryonic mesoderm cells. By combining 120 of these specific cells in precise ratios and providing the appropriate environment, they were able to witness the self-assembly of embryo-like structures.

Professor Jacob Hanna, one of the scientists involved in the project, highlighted the significance of this achievement in shedding light on the early stages of human embryo development. He explained that the first month of pregnancy is still relatively unknown, making it a critical period to study. The stem cell-derived human embryo model offers an ethical and accessible means of exploring this pivotal stage and closely mimics the intricate architecture of a real human embryo.
While this breakthrough may sound groundbreaking, it is important to note that the synthetic embryos created in this study are not actual human embryos. The researchers emphasized that it is illegal, unethical, and potentially impossible to use this method to achieve a pregnancy, as the assembly of the 120 cells would surpass the point at which an embryo can successfully implant into the womb lining.
Scientists hope that this synthetic embryo model will enable a better understanding of how different cell types emerge during early development and provide insights into genetic diseases. The controlled and ethical nature of this approach allows for comprehensive exploration without the ethical dilemmas associated with traditional methods.