Leaders of the D.S.M., the world’s most influential psychiatric manual, have been split for more than five years over whether to recognize postpartum psychosis as a distinct disorder.

In Trilobites, reporters aim to share new findings in the science world, be it interspecies friendships or discoveries of ancient fossils.

Filoplumes may be tiny, but these hairlike feathers enable nonstop flights that span thousands of miles.

The groups, including the American Academy of Pediatrics, say the C.D.C.’s revised vaccine schedule is not based on scientific evidence and will harm the public.

A pet cow named Veronika can scratch her own back with a broom — the first scientifically documented case of tool use in cows, researchers say.

The review looked at more than three dozen studies and found no evidence that acetaminophen increased the risk of neurodevelopmental disorders in children.

Generations of Times journalists have journeyed there with scientists. Their coverage traces humankind’s changing relationship with the most mysterious continent.

A professor at the University of California, Santa Cruz, he was a key contributor to a landmark paper that laid out how the universe came to look like it does today.

The Space Launch System and Orion capsule were transported to the launchpad before an astronaut mission that could launch as soon as Feb. 6.

Two regulatory rollbacks, along with a new A.I. experiment in Medicare, raise some worrisome questions.

Over two decades after negotiations began, the High Seas Treaty is designed to protect biodiversity in international waters by enabling conservation zones.

The case could affect thousands of claims that the widely used weedkiller causes cancer.

Construction can continue on an $11.2 billion project off the coast of Virginia, said to be 70 percent complete.

A federal judge said the Empire Wind project off Long Island would suffer “irreparable harm” if the Trump administration continued to hold up work.

Federal officials working on the new dietary guidelines had considered limiting men to one drink daily. The final advice was only that everyone should drink less.

Studying tree rings helped scientists pinpoint when Mount Rainier last sent a lahar down its steep slopes, which could help planners anticipate future mudflows.

Bad weather has postponed attempts to set up camp on the Thwaites Glacier. So researchers got onto the sea ice and met a local.

The members of Crew-11 — two American, one Russian and one Japanese — splashed down after one became ill, prompting an early return.

The U.S. Agency for International Development has been a major supporter of global agriculture research. Now many studies are being scuttled or scaled back.

The Trump administration has signed $11 billion in agreements with African nations, in deals tied to foreign policy goals.