Borstein was born in Highland Park, Illinois, a suburb north of the city of Chicago, in 1973 (according to her own official website), though some sources still say 1971. She was raised in Deerfield, Illinois. Borstein has two elder brothers. Her parents, Irv and Judy Borstein, are both mental health professionals. Borstein is Jewish. Her father is from Atlanta, Georgia. Her mother, a Holocaust survivor, was born and raised in Budapest, Hungary, and moved to the United States after the Hungarian Revolution of 1956. Borstein attended San Francisco State University.