Born into an artists' family, her parents are painters and her sister an actress. Mariana Otero studies literature at the University of Paris 8, and cinema at the Institut des Hautes Etudes Cinématographiques. As of 1987, she specialises in making documentaries and wins the prize for Best Documentary in Lisbon in 1994 for La Loi du Collège, and in Valladolid in 2003 for History of a Secret, a film about the disappearance of her mother. Into Our Own Hands is her sixth documentary.