Mary Louise Stepan (February 2, 1935 – December 15, 2021) was an American competition swimmer and Olympic medalist.

As a 17-year-old, Stepan represented the United States at the 1952 Summer Olympics in Helsinki.

[1] She received a bronze medal as a member of the third-place U.S. team in the 4×100-meter freestyle relay, together with teammates Jackie LaVine, Jody Alderson and Evelyn Kawamoto.

[1][2] Individually, Stepan also competed in the women's 100-meter freestyle, advanced to the event final, and finished seventh overall with a time of 1:08.0.

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