Researchers have captured the very first real-time, three-dimensional images and videos of a human embryo implanting into synthetic uterine tissue—revealing a key stage in reproduction. The resulting ...

A study based on a review of genetic and health information from more than 276,000 people finds strong support for a decades-old evolutionary theory that sought to explain aging and senescence. A ...

Since in many species, sperm is males' only contribution to reproduction, biologists have long puzzled about why evolutionary selection, known for its ruthless efficiency, allows them to exist. Now ...