Children are usually big enough to use a regular seat when they are 8 to 12 years old. Before allowing your children to use the regular seat and adult seat belt, make sure the seat belts fit them. The shoulder belt should lie across the chest, not the neck or throat, says the American Academy of Pediatrics (AAP). The lap belt should lie across the thighs, not the stomach. Children should be big enough to sit so that their back is against the back of the seat and their feet are hanging down, with the knees bent. Until your child reaches this size, he or she should remain in a booster seat.

Call your child's doctor if your child has fallen or taken a blow to the head and briefly lost consciousness, is acting strangely, or is vomiting. Seek emergency medical help after a fall or blow to the head if your child is unconscious; is breathing abnormally; is bleeding from the mouth, nose or ear; has pupils of unequal size; or is dizzy or confused.

Teens need calcium for growing bones. Most calcium in the diet comes from milk and other dairy products.

According to the CDC's National Health and Nutrition Examination Survey, 19.5% of children ages 6 to 17 were obese in 2011 to 2014. In 1976 to 1980, 5.7% of children ages 6 to 17 were obese.

In the United States, the average age for a girl to start menstruating is 12. The start of menstruation—called menarche—cannot occur until a girl's entire reproductive system has matured.

ADHD doesn't interfere with intellectual ability. Many ADHD kids are highly intelligent and creative.