Research in teens adds fresh evidence that the 1980s "crack baby" scare was overblown, finding little proof of any major long-term ill effects in children whose mothers used cocaine during pregnancy.

Some studies have linked pregnant women's cocaine use with children's behavior difficulties, attention problems, anxiety and worse school performance. But the effects were mostly small and may have resulted from other factors including family problems or violence, parents' continued drug use and poverty, the researchers said.

Four separate teams of scientists have said they were unable to replicate a highly publicized study that last year touted a cancer drug's success against Alzheimer's disease in mice.

"We wanted to repeat the study to see if we could build on it, and we couldn't," said David Borchelt, a professor of neuroscience at the University of Florida, noting that "it was important to publish the fact."

The World Health Organization voiced deep concern Thursday over the SARS-like virus that has killed 22 people in less than a year, saying it might potentially spread more widely between humans.

"We have a high level of concern over the potential... for this virus to have sustainable person-to-person spread," WHO deputy chief Keiji Fukuda told diplomats gathered in Geneva for the World Health Assembly, the U.N. agency's decision-making body.

Finnish researchers unveiled new data Thursday to link the Pandemrix flu vaccine to a higher risk of the sleeping disorder narcolepsy in adults

Finnish researchers unveiled new data Thursday to link the Pandemrix flu vaccine to a higher risk of the sleeping disorder narcolepsy in adults.

The H7N9 strain of bird flu can spread among ferrets and could do the same among humans under certain conditions, according to lab animal studies on the virus published Thursday.

So far there have been no known cases of human-to-human spread of the new virus, which has infected 131 people and killed 36 since it first emerged in China in March.

A blockbuster study in which U.S. researchers reported that they had turned human skin cells into embryonic stem cells contained errors, its lead author has acknowledged.

Shoukhrat Mitalipov nevertheless adamantly stood by the conclusions of the study published last week in journal Cell, which reported that human stem cell lines for the first time had been created via cloning.

Canadian health authorities lifted Wednesday what was effectively a ban on gay men giving blood, announcing new rules making men who have not had sex with men in the past five years eligible.

Under the previous regime, men who had sex with men since 1977, even once, were not allowed to donate.

An independent panel of experts on Wednesday recommended U.S. approval of a new Merck sleeping pill called suvorexant, but expressed concerns over the highest dosage and risks of drowsy daytime driving.

A majority of the panel voted that the drug was safe and effective in most cases, but experts were divided on the question of approving the safety of higher doses if lower doses did not appear to work for patients.

GlaxoSmithKline PLC says it's starting an unusual collaboration with the U.S. government to develop several antibiotics for both bioterrorism threats and bacterial infections resistant to current medicines.

Antibiotic resistance will become a global crisis, experts predict, because most drug companies have cut investment in antibiotics. Instead, they're developing more-lucrative medicines for chronic conditions or rare disorders.

A 33-year-old Polish man received a face transplant just three weeks after being disfigured in a workplace accident, in what his doctors said Wednesday is the fastest time frame to date for such an operation. It was Poland's first face transplant.

Face transplants are extraordinarily complicated and relatively rare procedures that usually require extensive preparation of the recipient over a period of months or years. But medical officials said the Polish patient's condition was deteriorating so rapidly that a transplant was seen as the only way to save his life. The patient is now being watched for any potential infections.