Erectile dysfunction might signal more than a need for the little purple pill, researchers said Tuesday in a study showing a link with heart disease and early death.

The Australian study -- the world's largest investigating links between erection problems and heart disease -- suggested erection problems could act as a warning sign of more serious health issues.

Microsoft founder Bill Gates said the battle to eradicate polio was one of the toughest the world has faced, but said it could be conquered by 2018.

Delivering the annual Richard Dimbleby lecture in London on Tuesday, Gates, the United States' richest man, said ridding the world of polio would be "one of the great moral and practical achievements of our age".

Hong Kong is considering designating baby formula a "reserved commodity" to ensure sufficient supply, an official said Wednesday, after mainland Chinese who flocked to buy it sparked shortage fears.

Hundreds of mainlanders have been stuffing tins of the baby milk powder into large bags and boxes near train stations at the border in recent days, part of a shopping spree before Lunar New Year that starts on February 10.

Spain's highest court on Tuesday suspended an unpopular one-euro surcharge for medical prescriptions introduced in Madrid this year to reduce the region's deficit.

The ruling by the Constitutional Court came in response to a suit filed by Prime Minister Mariano Rajoy's conservative government against the measure and just two weeks after the court ordered the suspension of an identical surcharge introduced last year in the region of Catalonia.

Research into the wonder material graphene and the neurochemistry of the human brain will receive up to two billion euros ($2.68 billion) in funding, the biggest research award of its kind in history, the European Commission said on Monday.

The two areas are beneficiaries of the Future Emerging Technology (FET) Flagship program, described as an "X-Factor for science", whose winners were chosen by leading scientists, a Nobel prize winner and industrialists.

Two Cambodian girls have died from bird flu, health authorities said Tuesday, raising the toll from the deadly infection in the kingdom to four so far this year.

The victims, a 17-month-old girl and a nine-year-old girl, from the southern provinces of Kampot and Kampong Speu, died Monday in hospital, the World Health Organization said in a joint statement with the Cambodian health ministry.

Gays and lesbians who come out about their sexual orientation are less stressed than those who remain in the closet, and often more relaxed than heterosexuals, according to a study released Tuesday.

Researchers at Louis H. Lafontaine Hospital, affiliated with the University of Montreal, tested the levels of cortisol -- a stress hormone -- and other indicators of strain in homosexuals, bisexuals and heterosexuals.

French health regulator ANSM has launched a probe into the drug Diane-35, used to treat acne and also as a contraceptive, after linking it to four deaths over the past 25 years.

Produced by the German drugmaker Bayer, Diane-35 is authorized in 135 countries and sold in 116. In 2012, about 315,000 women in France used the drug, ANSM said in a statement Sunday.

After banning smoking in public places, the Turkish government has gone one step further by clamping down on an ancient tradition -- the hookah, or water pipe.

As of Sunday it is no longer permitted to smoke the "hubbly-bubbly" in cafes, bars or restaurants as the conservative Islamic government cracks down on use of tobacco.

U.S. consumers are being offered a cornucopia of smartphone apps to track or manage health, but only a small number of people are using them, according to a survey released Monday.

The Pew Research Center's study found that only about seven percent of people surveyed used a smartphone app to track a health indicator like weight, diet, exercise routine or to monitor a chronic disease such as diabetes.