Bangkok — Scientists have developed human embryo-like structures without using sperm, an egg or fertilization, offering hope for research on miscarriage and birth defects but also raising fresh ethical concerns. Earlier this year, several labs around the world released pre-print studies that had not been peer-reviewed, describing their development of early human embryo-like structures. Now one group's research has been published in the peer-reviewed journal Nature, describing how they coaxed human embryonic stem cells to self-organize into a model resembling an early embryo. The research was welcomed by...