In 1973, 50 million Americans tuned in to ABC to witness a "battle of the sexes" tennis match: Billie Jean King vs. Bobby Riggs.

What few of us knew on that September day was that for King the tennis match was more about "social change" than anything else.

Just one year prior, President Richard Nixon signed a landmark law-Title IX, that requires gender equity for boys and girls in every educational program that receives federal funding.

Billie Jean King was "scared" and "afraid" that if she didn't win, people would find "a reason to weaken Title IX."

"I wanted the King/Riggs match to change the hearts and minds of people to more closely align with the legislation of Title IX," she said today at a hearing celebrating the 40th anniversary of the landmark legislation.

King reminded Senators during her testimony today on Capitol Hill that Title IX is not just about sports, though that is what it is most famously known for, but "at its very core," Title IX is truly about issues facing the nation-health, education, and labor.

Since its passage girls' participation in sports has gone from 1 in 27 to 2 in 5 at the high school level. And women now make up more than 50 percent of college graduates. But while overall sports for boys and girls continue to grow, gaps still exist. According to the National High School Athletics Participation Survey, since 2000 the gaps between males and females have actually grown.

King was joined on the panel by other high profile female leaders that Sen. Tom Harkin, D-Iowa, chairman of the Senate Health, Education, Labor and Pensions Committee, called "not only role models for other woman and girls but role models for all of us."

Dr. Mae Carol Jemison, the first woman of color in the world to go into space aboard the Space Shuttle Endeavour, Olympic Swimming Gold Medalist and law professor Nancy Hogshead-Makar, and the Superintendent of the U.S. Coast Guard Academy Rear Admiral Sandra L. Stosz all spoke about how Title IX personally and professionally impacted their own careers.

"In the 1960s on the south side of Chicago I remember being so excited about space exploration," physician and astronaut Jemison said. "When I finally did fly in space…the first thing I saw in space was Chicago… it was such a significant moment….l thought about that little girl who grew up on the south side of Chicago."

Jemison emphasized that it is important to keep moving equality forward because "the reality that we create for our children today will determine the fantasies that they hold for tomorrow."

The panelists also commented on the need for more women in STEM (Science, Technology, Engineering, and Math) careers, more teacher training and more resources for elementary school science teachers.

"Can you imagine trying to learn how to read without having a book to practice from?" Jemison said. "That doesn't mean putting a computer in front of them… allow the child to explore the world."

Jamison also commented on the problem of losing female talent and thereby female perspectives. When she was in medical school the standard treatment for breast cancer was mastectomy, she said. Only after more women joined the field did lumpectomy become more the norm; jokingly she put this treatment of women with breast cancer in a focus men could understand, saying no man would advocate losing his testicles.

Nancy Hogshead-Makar also pushed members of the committee to pass legislation making high school data, budgets and athletic department information more transparent and available to parents.

"Schools already have the data and have to report it to the department of education," Hogshead-Makar said. "This is just posting it on a public website so parents can get the data."

There were also some more light-hearted moments with Republic Sen. Mike Enzi explaining that his home state of Wyoming was the first to allow women to vote, hoping to gain enough votes to become a state.

As well as Sen. Barbara Mikulski, D-Md., attributing her "raging hormones" to guys who did not want to give equal access to women because they had too many "raging hormones."

"We are beyond raging hormones, we are beyond celebrity status…no longer viewed as novelty when we achieve things." Mikulski said to the panel: "We are very proud of you. You were the founding mothers; you did break the glass ceiling."

Since its passage Title IX has ensured equal opportunity for women, from fields like engineering and mathematics to the athletic fields as well as made it possible for the first woman Supreme Court justice, first woman in space, first speaker of the house among many others.

ABC's Tom Shine contributed to this report.