An experimental vaccine implant to treat skin cancer has begun early trials in humans, as part of a growing effort to train the immune system to fight tumors, researchers said Friday.

The approach, which was shown to work in lab mice in 2009, involves placing a fingernail-sized sponge under the skin where it reprograms a patient's immune cells to find cancerous melanoma cells and kill them.

The U.S. Food and Drug Administration says consumers shouldn't worry too much about levels of arsenic in rice — but should vary their diets just in case.

The agency, which monitors drugs and products for safety, released a study Friday of arsenic in 1,300 samples of rice and rice products, the largest study to date looking at the carcinogen's presence in that grain. Consumer groups have pressured the FDA to set a standard for the amount of arsenic that can be present in rice products.

Car windows are designed to protect you in an accident. But they won't necessarily protect you from the sun.

Automotive glass must meet a host of government standards in the U.S. and elsewhere. It has to let in the maximum amount of light to help drivers see. It has to shatter into tiny pieces instead of shards that might hurt occupants in a crash.

Children — like adults — are increasingly trying electronic cigarettes, according to the first large U.S. study to gauge use by teenage students.

Health officials say the study suggests many kids are now getting a first taste of nicotine through e-cigarettes and moving on to regular tobacco products.

Legislators in Puerto Rico are preparing to debate a bill that would allow people to use marijuana for medicinal purposes in this conservative U.S. territory, officials said Thursday.

The measure would create a system to legally produce the substance and allow state health officials to regulate it, said Rep. Jose Baez, one of the bill's two authors.

After falling four years in a row, U.S. births may finally be leveling off.

The number of babies born last year — a little shy of 4 million — is only a few hundred less than the number in 2011, according to a government report released Friday.

Doctors declared Wednesday that a pair of formerly conjoined twins were healthy and happy after they were successfully separated in a marathon "nerve-wracking" operation in India by a team of 40 specialists.

The one-year-old girls from Nigeria, sporting matching bright pink dresses, sat patiently on their parents' laps as doctors explained the separation last month during an 18-hour operation at a New Delhi hospital.

A video game can help elderly people fight cognitive decline, scientists reported in the journal Nature on Wednesday.

The novel game shows the brain is more "plastic," or versatile, in healthy ageing people than thought, which opens up new paths for warding off mental decay, its inventors said.

A new software tool may help doctors eliminate mistakes when judging whether a spot that turns up on a smoker's lung scan is cancerous or not, researchers said Wednesday.

The clinical risk assessment method described in the New England Journal of Medicine helped correctly decide nine times out of 10 whether a spot or lesion was benign or malignant.

Big anti-smoking messages on the front of cigarette packets may help deter youngsters tempted by tobacco but have little effect when they are on the back of the pack, research has found.

Touching on a subject that has stirred controversy in countries where pro- and anti-tobacco lobbies are fighting over smoking controls, investigators looked at data from a large survey among British teenagers.