Ava is a 16-year-old high school student who has asthma. She hates taking medicine, and she doesn't like to use the inhaler her doctor prescribed for her, especially at school where her friends might see her. Most days she tries to get out of PE, telling her teachers her asthma is bothering her. She started smoking a few months ago, even though it makes her cough.

Arturo was diagnosed with diabetes when he was very young. He has learned to give himself insulin shots. Lately, he's started thinking about using the insulin pump. Together, he and his mom talked to a nutritionist about his food plan, and he knows it's important to eat healthful foods at regular intervals.

Callie is in her last year of college. She went to the doctor last month to have a large mole on her back checked. The doctor said the mole is cancerous. Callie has always loved to have a dark tan. As a teenager, she spent hours by the pool or at the beach getting a tan. Once or twice, she had a really severe sunburn.