Canadian-born American pathologist, noted for her work on the stages of a cell's progression from a normal to a cancerous state.

Stern received her medical degree from the University of Toronto (1939) and the following year went to the United States, where she became a naturalized citizen in 1943. Stern was one of the first specialists in cytopathology, the study of diseased cells. From 1965 she was professor of epidemiology at the University of California at Los Angeles.

Stern published in 1963 what is believed to be the first case report linking a specific virus to a specific cancer—that of the herpes simplex virus to cervical cancer. She was also the first (1973) to report a definite link between the prolonged use of oral contraceptives and cervical cancer, connecting the use of the contraceptive pill with cervical dysplasia, often a precursor of cancer. In her most noted work in this field, Stern studied cells cast off from the lining of the cervix and discovered that a normal cell goes through 250 distinct stages of cell progression before reaching an advanced stage of cervical cancer. This prompted the development of diagnostic techniques to detect cervical cancer in its early stages, thus making it, with its slow rate of metastasis, one of the types of cancer that can be successfully treated by prophylactic measures (i.e., excision of abnormal tissue).