Scientists have created synthetic human embryos using stem cells, sidestepping the need for eggs or sperm. The model embryos resemble those in the earliest stages of human development and do not have a beating heart or the beginnings of a brain, but include cells that would typically go on to form the placenta, yolk sac and the embryo itself. It is not yet clear whether these structures have the potential to continue maturing beyond the earliest stages of development. Embryos may only be cultivated for up to 14 days in a lab, and it would be illegal to implant them into a patient’s womb.  READ MORE…