This is the VOA Special English Health Report.

Parents might tell teenagers, "Act your age." But some scientists say that is exactly what teens are doing. They say that while teenagers can look all grown up, studies have found that their brains are still developing.

How much this explains their behavior, though, is a subject of debate.

Jay Giedd of the National Institutes of Health in the United States is a leader in this area of research. Doctor Giedd has been studying a group of young people since nineteen ninety-one. They visit him every two years for a new M.R.I., or magnetic resonance imaging, of their brains.

He says considerable development continues throughout the teen years and into the twenties. A part of the brain called the dorsal-lateral prefrontal cortex appears especially undeveloped in teens. Researchers believe that among its duties, this area controls judgment and consideration of risk. 

So, in theory, its underdevelopment may explain why young people seem more willing to take risks like driving too fast.

Laurence Steinberg is a psychology professor at Temple University in Philadelphia. He says stronger laws, and stronger parental control, are needed to protect teens from themselves. That includes raising the age for driving. He says research finds that teenage brains are not fully equipped to control behavior.

Other scientists, however, say there is not enough evidence to make a strong case for such findings.

Psychologist Robert Epstein, a visiting scholar at the University of California, San Diego, notes that teen behavior differs from culture to culture. He says behavior depends for the most part on socialization. As he sees it, if teenagers are with adults more, and treated more like adults, that will lead to better, safer behavior.

But is that always true? Mike Males at the Center on Juvenile and Criminal Justice in San Francisco is a founder of youthfacts.org. He suggests that all of this talk lately about "brainless" teens could possibly be an attempt to take away attention from the reality.

Writing this week in the New York Times, he says it is middle-aged adults -- the parents -- whose behavior has worsened. In his words, "if grown-ups really have superior brains, why don't we act as if we do?"

And that’s the VOA Special English Health Report, written by Caty Weaver. For more health news, go to voaspecialenglish.com. I’m Faith Lapidus.