Prepon was born on March 7, 1980 in Watchung, New Jersey. She is the youngest of five children, daughter of Marjorie a high school teacher, and Michael Prepon, an orthopedic surgeon. Her father was of RussianJewish descent and her mother is of English, German and Irish Catholic background. Her maternal great-great-great-grandfather was Union Army GeneralJoseph Bradford Carr.Prepon's father died during heart surgery in 1993 at age 49; Prepon was 13 years old at the time. She attended Watchung Hills Regional High School. She studied at Caroline Thomas' Total Theater Lab in New York City.
