While an involvement in sports helps both boys and girls, girls benefit in very specific ways from joining teams and having a strong commitment to a physical activity. For example, high-school female athletes are less likely to smoke than nonathletes. And a 1998 study definitively linked sports involvement and lowered rates of teenage pregnancy.

Following are more benefits that girls enjoy from sports:

• Girls involved in high-school sports have higher science grades and test scores. They are less likely to drop out of high school and more likely to go on to college than their nonathletic counterparts.

• Girls who engage in regular physical activity are less likely to be overweight. They have lower levels of blood sugar, cholesterol and tryglycerides, and lower blood pressure than nonexercising girls.

• Girls who participate in sports teams feel better about their bodies than those who don't.

The good effects last for years. Girls who exercise develop stronger, denser bones, and are less likely to develop osteoporosis. Also, even small amounts of exercise per week can reduce the risk of breast cancer in later life.

Sports can help in other areas of life — 80 percent of female Fortune 500 executives described themselves as “tomboys” and were involved in athletics when they were young.