 In 1945, she joined him in Oak Ridge, Tennessee and spent a year working on the Manhattan Project, researching the biological effects of radiation.The two married in 1946 and returned to Chicago where Marian received her Ph.D. in immunology from the University of Chicago in 1949.Marian's sister-in-law later recalled that her professor didn't want to give her a Ph.D. because Marian was pregnant and he thought she would waste it.