Marysia Rozenszajn was born on June 19, 1941, in
Białystok, at that time part of
Soviet-occupied Poland; her parents Izak (Włodek) Rozenszajn and Bela Kaufman Rozenszajn were from
Warsaw, but had moved to Białystok to escape the Nazis. Her father died four days after her birth, from the initial bombings of the
Battle of Białystok–Minsk. After this battle, Nazi Germany took over eastern Poland and set up the
Białystok Ghetto to confine the Jews of Białystok, including Rozenszajn and her mother. In 1943, Rozenszajn's mother Bela obtained documents identifying her as being Catholic Polish, named Paulina Pakulska, which she used to escape Białystok with her daughter and begin working as a maid in
Tykocin. However, in late 1943 or early 1944, Bela was arrested as a
partisan, leaving Rozenszajn abandoned on the streets of Tykocin. She was found and taken care of by Lucyna and Wacław Białowarczuk, who had no children and raised her as their own, covering her dark hair in public, and bringing her to pray with them at the Catholic church. Tykocin returned to Soviet control in the
Belostok Offensive of July 1944. Rozenszajn continued to live with the Bialowarczuks until in 1946 being reunited with her mother Bela, who had survived the
Ravensbrück concentration camp and lived for a year as a refugee in Sweden. After spending several months becoming reacquainted with each other and living with the Białowarczuks, Maria and Bela Rozenszajn returned to Warsaw, but remained in contact with the Białowarczuks, who were named
Righteous Among the Nations for risking their lives to save Rozenszajn. In 1948, Bela Rozenszajn died in an automobile accident. After briefly living with an uncle, Maria was adopted by Alicja Dworzecka and Arkadiusz Dworzecki, who were Polish Jews. It was from this adoption that she obtained the surname Dworzecka that she would use in her professional career as a physicist. ==Education and career==