Scientists at the Weizmann Institute of Science have successfully grown an embryo model that closely resembles a 14-day-old human embryo using stem cells. This breakthrough could provide an ethical way of studying and understanding the early stages of human development, which is poorly understood and a major source of miscarriage and birth defects. The embryo model, made without sperm, eggs, or a womb, even released hormones that turned a pregnancy test positive in the lab. The starting material for the model was naive stem cells that were reprogrammed to have the potential to become any type of tissue in the body. Chemicals were then used to coax these stem cells into becoming four types of cells found in the earliest stages of a human embryo. About 1% of the mixture spontaneously assembled into a structure resembling a human embryo. The embryo models were allowed to grow and develop until they reached a stage comparable to an embryo 14 days after fertilization, the legal cut-off for normal embryo research in many countries.
The hope is that these embryo models can help scientists understand how different types of cells emerge, observe the earliest steps in organ development, and gain insights into inherited or genetic diseases. They could also potentially improve the success rates of in vitro fertilization (IVF) and test the safety of medicines during pregnancy. However, the current 99% failure rate of the models would need to be improved to better understand miscarriage or infertility. The work also raises ethical questions about how these models should be regulated as they closely resemble human embryos. While they are not considered normal embryos, some argue that they should be treated with the same level of regulation and ethical considerations.
Overall, this research represents a significant step forward in understanding early human development and could have far-reaching implications in various fields, including reproductive medicine and genetics. However, further research and improvements are needed before these embryo models can be used extensively. The potential applications of this technology, as well as the ethical considerations surrounding it, will continue to be topics of discussion and debate among scientists, policymakers, and the general public.