The enamel on our teeth is the hardest tissue on the human body. A new study looks at the nanoscale structure of enamel from teeth dating as far back as 18 million years ago to see how it's changed.

A new twice-yearly HIV prevention injection could transform South Africa's fight against the epidemic — but U.S. aid cuts and limited doses threaten to slow its impact.

Despite a diminished federal presence, public health departments are preparing for common ailments that could afflict fans who gather for the event — and are keeping an eye on the Ebola outbreak, too.

Scientists are building autonomous robotic labs powered by artificial intelligence. The goal, they say, is for these robots to take over human researchers' most laborious, time-consuming tasks.

For a smooth, rewarding and drama-free couples trip, take as much stress out of the equation as you can — and get comfortable with the fact that a fight may arise (and that's OK).

Some jurisdictions have weakened their public health authorities in response to criticism of lockdowns, school closures, mask mandates, vaccine requirements and other COVID-era restrictions.

Homing pigeons rely on a variety of signals to navigate, including magnetism. But it hasn't been clear how they detect magnetic cues. Researchers propose the answer may be found in the birds' livers.

In April, at a bald eagle's nest in Washington, D.C., there was much anticipation about eggs that were expected to hatch near the end of the month. Unfortunately, the nest failed, and the eagles have left it.

In a remote mining town in Ituri province, doctors, many of them with little or no training, are fighting the Ebola virus.

From Vancouver to Mexico City to Philadelphia, 16 cities across Canada, Mexico and the U.S. are preparing to host millions of soccer fans from around the world for the 2026 World Cup.