WASHINGTON (NEXSTAR) — The first lady on Wednesday celebrated the 50th anniversary of Title IX, a landmark federal civil rights law requiring equal opportunities for women in education and sports.

“Title IX created space for girls and women to be more,” Jill Biden said.

The 37-word provision was tucked into the 1972 Higher Education Bill when it appeared ratification of the controversial Equal Rights Amendment could stall. Requiring equal opportunities for men and women at federally-funded schools, it opened the door for millions of women to attend college and play sports.

The first lady was joined in the celebration by famous tennis player and activist Billie Jean King. She was a college athlete before Title IX became law and said she was forced to work two jobs while her male counterparts enjoyed full scholarships.

“We can never understand inclusion until we’ve been excluded,” King said.

She called Title IX “one of the most important pieces of legislation of the 20th century.”

“It’s incredible to see how much has changed in my lifetime,” Jill Biden said, adding “we’re not done yet.”

The celebratory event was hosted by the U.S. Department of State, which for the past decade has used Title IX to promote women’s sports and education globally.

“The State Department’s Global Sports Mentoring Program has empowered girls thousands of miles away,” Biden said.

International partners say the program has transformed lives abroad, with Global Sports Mentoring Program Kenya partner Grace Kiraguri saying, “we are stronger together.”