Why the flu is worse in winter than summer has long baffled scientists. A new finding suggests that the virus multiplies when it's cold because the humidity of the air is lower.

A new study says your social networking style is about 50 percent genetic, which means your DNA helps dictate who your friends are and how many of them you have.

Tiny new wireless machines called microgrippers can manipulate microscopic objects—a breakthrough that could lead to devices that can perform surgery, a new study says. With video.

The "Exxon Valdez of coal ash" in Tennessee may poison wildlife for years to come, "but no one seems to be talking about it," conservationists say.

The world's first study using controversial embryonic stem cells has been approved by the Food and Drug Administration. The treatment will be aimed at helping those with spinal cord injuries.

A baby lemur "needs to be protected," a hospital goes Hello Kitty crazy, Obama illuminates Kenyan well-wishers, and more in the week's best news photos.

Conservationists say herders are poisoning lions in Kenya with the pesticide Furadan, also known as Carbofuran, to keep them from killing livestock.

Hardcore coffee, tea, and soda fans may be more prone to hallucinations and other mental disturbances, new research suggests.

Up and down California's coast, brown pelicans are dying in alarming numbers, and sick and disoriented pelicans have been found wandering on roads and in other unusual places—and scientists are stumped.

A simple sandwich bag can bring new hope to the parents of premature babies.

Monkeys from a now-defunct research facility are roaming wild in southwestern Puerto Rico, threatening farmers' livelihoods, and causing public health concerns

An increasing number of Americans are heading overseas for expensive, unregulated stem cell treatments. U.S. doctors today issued new warnings against such procedures, but for the desperate, hope is worth the money.

Seized during a Malaysian raid, the owls shocked wildlife-trade monitors. The sizes of this and another November seizure point to organized crime, experts say.

New "robo legs" make walking and climbing stairs easier. "I felt like I had springs in my legs," said a reporter who had tested the high-tech apparatus.

Do you want corn with that? A new chemical analysis of corn-laden burgers, fries, and chicken sandwiches may suggest bad news for our health and the environment.