premise: Fidel Castro is an only child.
hypothesis: Fidel Castro . Born in Birán , Oriente as the son of a wealthy Spanish farmer , Castro adopted leftist anti-imperialist politics while studying law at the University of Havana . After a year 's imprisonment , he traveled to Mexico where he formed a revolutionary group , the 26th of July Movement , with his brother Raúl Castro and Che Guevara . In 2006 he transferred his responsibilities to Vice-President Raúl Castro , who was elected to the presidency by the National Assembly in 2008 .