According to the article, scientists have created synthetic human embryos using stem cells, without the need for eggs or sperm. These embryo-like structures resemble those in the earliest stages of human development, but they do not have a beating heart or a brain. They are not considered human embryos, but rather embryo models. However, the work also raises serious ethical and legal issues, as there are no clear regulations governing the creation or use of these synthetic embryos. Some bioethics experts have expressed concern about the implications of these models for the definition and respect of human life.