Mariela Castro, director of the National Center for Sex Education in Cuba, had applied for permission to travel outside New York -- where she is attending meetings at the United Nations -- to receive an award at the Equality Forum 2013 Summit next week, The New York Times reported Thursday.
Like other Cuban diplomats, she cannot travel farther than 25 miles from the U.N. without State Department permission.
Malcolm Lazin, the forum's executive director, said Castro has won an international reputation as an advocate for homosexual rights.
"We were shocked," he said of the decision.
Castro has a diplomatic visa to be in New York. U.S. diplomats in Havana face similar restrictions.