Ever watched a teen skulk in the corner of a toddler-packed pediatrician's waiting room, obviously wishing to be anywhere else? Adolescents aren't just big kids, and too many start falling through cracks in the health care system when they pass the stage of preschool shots and summer camp checkups - what a major new report calls missed opportunities to shape the next generation's well-being. The period between ages 10 and 19 is unique, bringing more rapid biological changes than perhaps any age other than infancy. Even though most of the nation's 42 million adolescents seem to be thriving, it is a time of risk-taking and pushing boundaries in ways that can mean immediate consequences: Car crashes, experimenting with alcohol or drugs, teen pregnancy, sexually transmitted disease. And it's also an age when many of the habits that determine good health during adulthood are set, or not. "They are quite literally our future. If we don't take good care of them, there's a strong likelihood when they're running the ship they're not going to have a good time running the ship," said Dr. Frank Biro of Cincinnati Children's Hospital's long-running adolescent medicine program. Yet the system of care for tweens and teens is fragmented and poorly designed. Few doctors specialize in adolescents' complex needs, or provide comprehensive care that earns their trust, concludes a recent probe by the National Research Council and Institute of Medicine. Most at risk are the poor. The result: The past decade has brought declines in teen pregnancy and smoking but little other overarching progress. Tweens and teens increasingly are overweight; physical activity's dropping; chronic diseases like asthma and diabetes are on the rise; and injuries, chiefly from car crashes, remain this age's leading cause of death. While 20-somethings tend to see primary-care doctors the least, a gradual falloff begins in adolescence. Only a fraction of tweens and teens have been screened for risky behavior so doctors can intervene before a problem arises, the report found. Between 10 percent and 20 percent of adolescents annually experience a mental health disorder, such as depression or anxiety, with less access to that specialty care. Five million are uninsured, too often even left out of federal-state programs designed to provide health coverage to children. Yet half of deaths among adults are due to health-related behaviors that often start during adolescence. "A 10-year-old is probably the healthiest person in America," notes Dr. Frederick Rivara of the University of Washington, a co-author of the new report. "Something happens between age 10 and age 25." Teens do tend to see a doctor, clinic or school-based care program somewhat regularly, if not because parents demand it, then for vaccinations or the 15-minute physical required by sports teams. But the report notes it can take at least 40 minutes to do a thorough adolescent checkup, including screening and counseling for risky behaviors - the kind that may prompt enough trust for the teen to return with a problem he or she doesn't want Mom to know about. But with fewer than 500 doctors certified as adolescent medicine specialists between 1996 and 2005 - some states have none - most families will need to hunt a pediatrician or family physician with the communication and social skills and, perhaps more importantly, the true interest to engage a teen. "Adolescents have so much energy. They see the world so differently than you or I," says Biro, Cincinnati's adolescent medicine chief, who wasn't part of the report and says society's stereotype of sex and drugs isn't the typical teen. The relationship starts with the doctor making clear that the adolescent has a right to patient confidentiality that grows with age, although he or she must work with the parents, too. As Biro describes the balancing act: "As long as you're not hurting yourself, another person or getting hurt by another person, I will hold that information confidential. ... If there's a direct health risk that could involve their life, then I will share that." Then comes recognizing that the early teen years are when kids move from concrete thinking to more abstract thought - they begin to connect the dots, Biro explains. They may assume the doctor connected the dots the same way, meaning a girl who complains of stomach pain may not volunteer that she's fears pregnancy. "It's not that they're withholding information. They figure they've just told you everything you need to know because the rest of it you should be able to figure out," Biro says. "I prove to them I am indeed about as smart as mud and I have to ask them more probing questions."