An hour's drive south of Canada's capital, past snow-covered pine forests and farmland, Chuck Rifici is growing marijuana at an old Hershey's factory.

He plans to sell it for medical use under a new government scheme starting on April 1 that will ban home cultivation in favor of large commercial greenhouses.

The EU will carry out a second round of tests to see if horsemeat is being passed off as beef, after a scandal last year rocked public confidence in food safety standards.

The European Commission said Friday that experts had approved more DNA tests after last year's found that 4.6 percent of examined products contained horsemeat without being labelled as such.

Two public health experts warned Saturday about the stunting effects that a wide array of industrial chemicals, including toothpaste ingredient fluoride, may be having on child brain development, in a report some called alarmist.

The pair, Philippe Grandjean of the Harvard School of Public Health and Philip Landrigan from New York's Icahn School of Medicine, said the number of chemicals known to hinder child brain development have doubled from six in 2006 to 12 today.

Mothers may say they don't care whether they have a son or a daughter, but their breast milk says otherwise.

"Mothers are producing different biological recipes for sons and daughters," said Katie Hinde, an evolutionary biologist at Harvard University.

Leftist lawmakers on Thursday proposed allowing the sale of marijuana within Mexico City, seeking to join Uruguay and the U.S. states of Washington and Colorado in creating legal markets for the drug.

The bill is vague on many key points and faces legal hurdles that may be impossible to overcome but it creates at least the possibility of an island of legalization of one drug in a nation that has been devastated by the fallout from the U.S.-backed fight to stop the northbound flow of recreational narcotics.

The reason people have more heart attacks when air pollution levels rise may have been revealed by a study on the impact of the BP oil spill on tuna, scientists said Thursday.

Heart problems in humans and fish have long been linked to air pollution and oil spills respectively. But researchers had not yet sorted out exactly how the toxic compounds found in oil interfere with heart cells.

Moderate or heavy smokers who quit tobacco get a boost in mental wellbeing that, for people who are anxious or stressed, is equivalent to taking anti-depressants, a study said Thursday.

British researchers examined 26 published investigations into the mental health of smokers.

Baby talk is more than just bonding: chatting with your infant spurs important brain development that sets the stage for lifelong learning, researchers said Thursday.

And while high-pitched, sing-song tones may capture your baby's attention, the best way for them to learn is to be spoken to like adults. At least when it comes to vocabulary and sentence structure.

Researchers in Japan will trawl through huge amounts of data to search for possible precursors to Alzheimer's Disease in a bid to identify who might develop a condition affecting millions around the world.

The study, which involves the healthcare arm of General Electric, will be based on a health survey that Hirosaki University in the northern prefecture of Aomori has been conducting for years.

There may be a link between weather and the risk of suffering a stroke, say researchers who analyzed climate trends and hospital records on millions of Americans.

Cold weather, high humidity and big daily temperature swings seem to land more people in the hospital with strokes. As it got warmer, risk fell — 3 percent for every 5 degrees, the study found.