Scientists recently created the first “synthetic” embryo to develop a brain and beating heart.

What differentiates synthetic embryos from those created via IVF is that these so-called embryo “models” are produced asexually — without eggs or sperm. Researchers applied chemicals to pluripotent stem cells to encourage them to develop into the types of cells that form embryos. Coaxing these cells together, scientists observed that a small minority of them subsequently self-assembled as they are programmed to do, into embryos with brains and beating hearts.