NEW YORK (AP) -- Serena Williams and Mia Hamm are helping Billie Jean King spread the word about keeping girls in sports in conjunction with the 40th anniversary of Title IX.
Williams, a 13-time Grand Slam champion, is featured in national magazine ads that show her as a young girl whacking a tennis ball and the words: "If I walked away then, I wouldn't be here now."
Hamm, the former U.S. soccer star, has tweeted about the Women's Sports Foundation's campaign to promote active and healthy lifestyles. Girls drop out of sports at twice the rate of boys by age 14, according to the WSF.
The foundation that King founded wants to keep girls in the game longer through its youth programs, offset messages focusing on looks rather than abilities and help them become successful leaders.
If girls are involved in sports or physical activity by age 10, they're much more likely to be active at 25, King said. That can help fight obesity, which the Center for Disease Control reports has more than tripled in the past 30 years among ages 6-19.
Title IX passed on June 23, 1972, and opened doors for girls and women by banning sex discrimination in all educational programs - including sports - that receive federal funds.
That marked a banner year for the 28-year-old King, who won Grand Slam titles at Wimbledon, the U.S. Open and French Open to earn the cover of Sports Illustrated as "Sportswoman of the Year."
King spoke this week at a Senate hearing on Title IX and recently discussed with The Associated Press the importance of the law and the pivotal role her parents played in her sporting career.
"When I was about 5, the boys wouldn't let me play. He says, `Everybody come over here, if you don't let Billie play, no one's playing. So let her play, she's very good, she can hold her own with you guys.' And we're just tiny. I was so embarrassed, but then I was so proud at the same time."