Scientists make artificial human embryos without sperm or egg

Researchers at the Weizmann Institute of Science have created an artificial "embryo model" that mimics a 14-day-old human embryo without using sperm, eggs, or a womb. They achieved this by starting with pluripotent stem cells, which can develop into various tissue types, and coaxing them into becoming four cell types found in early human embryos. Think of it like making a cake with cells instead of flour and sugar. By mixing these cells in specific ratios, they created an artificial embryo without harming any eggs.

These artificial embryos grew to resemble 14-day-old embryos, which is the legal research limit in many countries. The detailed structure of these artificial embryos closely resembled real embryos, including features like the placenta-like trophoblast and nourishing cavities.

Reference: Oldak, B., Wildschutz, E., Bondarenko, V. et al. Complete human day 14 post-implantation embryo models from naïve ES cells. Nature (2023). https://doi.org/10.1038/s41586-023-06604-5