The Zeta Phi Beta sorority is blocking transgender women from its organization, according to a document leaked to the Washington Blade newspaper.

The organization founded 99 years ago on the campus of Howard University, in Washington D.C., adopted a “diversity statement” on Jan. 12 of this year that declares “an individual must be a cisgender woman” to join the organization, the Blade reports. The measure was adopted by Zeta Phi Beta’s International Executive Board, according to the news organization.

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As part of the same statement, the sorority also declares that it “values all people, regardless of race, age, gender, gender expression, ability, disability, creed, religion, or walk of life.”

The Blade‘s source forwarded the statement earlier in April. Zeta Phi Beta did not respond to multiple requests for comment, according to the Blade.

The revelation came Thursday, one day before singer/actress Janelle Monáe, White House hopeful Elizabeth Warren and other prominent people were celebrating gender and sexual differences by honoring Lesbian Visibility Day.

“We love you! #LesbianVisibilityDay,” tweeted Monáe along with an emoji of a rainbow.

“On #LesbianVisibilityDay, I want to be clear: You matter. We see you. We won’t stop fighting until everyone is free to love without fear or discrimination,” tweeted Warren, a Democratic U.S. senator from Massachusetts.

Zeta Phi Beta, whose colors are blue and white, has more than 100,000 members in 800 chapters spread across the United States, Africa, Europe, Asia, and the Caribbean, according to its website.

The Blade reports that sororities and fraternities have traditionally expressed hostility toward the LGBTQ community.

Five students formed Zeta Phi Beta at a time when the Ku Klux Klan was running rampant, but the Harlem Renaissance was also offering an outlet for Black people to demonstrate their talents, according to the sorority website.

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They sought to foster unity and encourage scholastic achievement, according to the site, which continued:

“These women believed that sorority elitism and socializing overshadowed the real mission for progressive organizations and failed to address fully the societal mores, ills, prejudices, and poverty affecting humanity in general and the Black community in particular.”