Playing sports impacts girls’ health in the future. As women, they are more likely to be active, happy, energetic, and healthy. And they are less likely to have health-related issues in the long term.
From girls to women
Women who were active as children enjoy the protective effect on health in later years and experience lower incidence of osteoporosis, diabetes, high blood pressure, heart disease, obesity, and endometrial, colon, and breast cancers. 
Women who had the highest physical activity during adolescence and young adulthood were 20% less likely to get breast cancer, according to the findings from 23 studies. 
Women who have grown up playing sports are more motivated to stay active as adults because they have experienced higher levels of neurotransmitters such as dopamine and serotonin. In other words, their brains have an established reward-feedback loop associated with exercise, which keeps women motivated to exercise. 
Women who exercise have healthier weights, lower levels of blood sugar, cholesterol and triglycerides, and lower blood pressure than women who don’t exercise. 
Women experience fewer symptoms of depression in young adulthood if they participated in sports in high school. 
Participation in sports extends beyond the life of just the girl who plays.
Scientists have found evidence of exercise-related benefits even earlier in life, passed on by mothers who exercise during pregnancy or even prior to conception.
“Given that the mother is sharing her circulation with the offspring, all kinds of changes are passed on in terms of hormone levels or blood lipid levels, all of which affect the energy storage, oxygen capacity and muscle health of the child at birth. This has an impact on their natural ability to exercise, but also perhaps on their motivation to exercise at a subconscious level. This will then go on to benefit them throughout life.”
—Ted Garland, University of California 
Research suggests that if people play sports, their daughters will be more likely to play.
The more girls participate now, the more future girls will have mothers to look up to. With role models who can speak to their own experiences, girls will feel more confident in their abilities to thrive in intense competition and believe that they are tough.
Girls who play sports can become mothers, aunts, coaches, and teachers who show girls that being athletic and being feminine are not mutually exclusive.
A 2004 study by researchers at the University of Southern California suggests that if a mother plays or played organized sports, her daughter is more likely to play.