The first steps of human development—those that occur within the first few weeks of pregnancy—remain mysterious in many ways. Within a week of fertilization, human embryos form a blastocyst, which ...

Researchers have used naïve pluripotent stem cells to create an embryo model that looks and acts like a natural human embryo. They say it’s an ethical way of gaining a better understanding of ...

The earliest days after fertilization, once a sperm cell meets an egg, are shrouded in scientific mystery. The process of how a humble single cell becomes an organism fascinates scientists across ...

Four teams have coaxed human stem cells to organize themselves into embryo-like forms. The advance could shed light on fertility. By Carl Zimmer In its first week, a fertilized human egg develops into ...

Cells in culture typically form continuous sheets, like skin. But in 2017, bioengineer Jianping Fu realized that if he cultured human stem cells in a 3D scaffold, they would spontaneously organize ...

Descriptions of the embryo go back at least to the time of Aristotle, but it has only been since the late 19 th century and early 20 th century that advances in experimental approaches allowed ...