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 ...

When Homo sapiens and Neanderthals interbred, a genetic variation affecting red blood cells may have hindered reproduction in ...

Hormones are secreted by glands in the endocrine system. During puberty, hormones create changes in physical and emotional characteristics. In this video, Greg Foot describes the interaction of FSH, ...

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 ...