Rob Stein

A scientist in Sweden has started trying to edit the DNA in healthy human embryos, NPR has learned.

The step by the developmental biologist Fredrik Lanner makes him the first researcher known to attempt to modify the genes of healthy human embryos. That has long been considered taboo because of safety and ethical concerns.

Hundreds of clinics around the country are offering to treat a long list of health problems with stem cells.

The clinics claim that stem cells found in fat tissue, blood, bone marrow and even placentas can help people suffering from arthritic joints and torn tendons to more serious medical problems, including spinal cord injuries, Parkinson's disease and strokes. Some even claim the cells can help children with autism.

But leading stem cell researchers say there's not enough evidence to support the clinics' claims.

The federal government announced plans Thursday to lift a moratorium on funding of certain controversial experiments that use human stem cells to create animal embryos that are partly human.

The National Institutes of Health is proposing a new policy to permit scientists to get federal money to make embryos, known as chimeras, under certain carefully monitored conditions.

There's finally some good news about childhood asthma in the United States: After rising for decades, the number of children with the breathing disorder has finally stopped increasing and may have started falling, according to a government analysis.

"That was a big surprise," says Lara Akinbami of the National Center for Health Statistics. "We were expecting the increase to kind of continue. But in fact we saw the opposite."

The Food and Drug Administration Thursday proposed regulating e-cigarettes for the first time.

The agency unveiled a long-awaited rule that would give it power to oversee the increasingly popular devices, much in the way that it regulates traditional cigarettes.

This year's flu season started about a month early, prompting federal health officials to warn it could be one of the worst in years. They're urging everyone to get their flu shots.

But like every flu season, there are lots of reports of people complaining that they got their shot but still got the flu. What's up with that?

Well, as Michael Jhung of the Centers for Disease Control and Prevention explains, there are lots of possible reasons.