Mariela Castro will attend the Equality Forum's annual conference on civil rights for lesbians, gays, bisexual and transgender people, according to Malcolm Lazin, the advocacy group's executive director.
Lazin, who had blasted the State Department's travel denial last week, said organizers are "delighted" at the change of heart.
"She is unquestionably the leader for progressive change for the LGBT community in Cuba," Lazin said Tuesday. "Her accomplishments are nothing short of remarkable."
A U.S. official confirmed that Castro has been authorized to go to the event. The official spoke on condition of anonymity because visa records are confidential.
High-ranking Cuban government officials and Communist Party members cannot enter the U.S. without special dispensation. But Cuban academics, scientists and entertainers are finding it easier to visit because President Barack Obama's administration has relaxed travel restrictions.
Castro, a married mother of three, is the niece of retired Cuban strongman Fidel Castro. She is also the director of Cuba's National Center for Sex Education, part of Cuba's public health ministry, and is the country's most prominent gay rights activist.
Castro has instituted awareness campaigns, trained police on relations with the LGBT community and lobbied lawmakers to legalize same-sex unions. She was elected as a deputy in Cuba's parliament in February.
On Saturday in Philadelphia, she will speak about her experiences and receive an award from the Equality Forum.
Lazin said that Castro had accepted the group's invitation months ago and that he was surprised by the initial visa denial because she had been allowed to attend an academic conference in San Francisco last year.
But some Cuban-American lawmakers blasted that decision, calling Castro a shill for her family's Communist dictatorship. At the time, Sen. Robert Menendez, D-N.J., called her "a vociferous advocate of the regime and opponent of democracy."
Menendez was traveling in Central America on Tuesday and was unavailable for comment, a spokesman said.
Associated Press writer Matthew Lee in Washington contributed to this report.
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