She was born Gerda Hedwig Kronstein in Vienna, Austria on April 30, 1920, the first child of Ilona Kronstein (née Neumann, 1897, Budapest–1948, Zürich) and Robert Kronstein (1888, Vienna–1952, Vaduz), an affluent Jewish couple. Her family are originating and relating to Breslau, Berlin, Léva [hu] (German: Lewenz, Levice [sk]), Turdossin [hu] (Turdos, German: Turdoschin, Tvrdošín [sk]) (Upper Hungary), Helishoy (German: Holleschau, Holešov [cs]) (Moravia), and Reichenberg (Liberec [cs]) (Bohemia). Her father was a pharmacist, and her mother an artist, with whom Gerda, according to her autobiography, had a strained relationship as a child. As an adult, Gerda believed that her mother Ilona struggled because she did not fit in the role of a Viennese wife and mother. Gerda had a younger sister, and they attended local schools and gymnasium.