When her license to teach was revoked by the bishop because of her critical position in matters of faith, the university created a nondenominational chair of History of Religion.

Her 1988 book Eunuchs for the Kingdom of Heaven, criticising the Catholic Church's stance on women and sexuality, was published in several editions, and translated in 12 languages.

[5] After nearly seven years' study of Protestant theology in Bonn, Basel, Oxford, and Montpellier,[6] Heinemann converted to Catholicism in 1953,[7] when she married a Catholic religion teacher, Edmund Ranke.

[8] In 1987 Bishop of Essen Franz Hengsbach withdrew her license to teach Catholic theology for disputing the virgin birth of Jesus.

[8] In 1999, Ranke-Heinemann was a candidate for President of Germany, without party membership, but lost to Johannes Rau, the husband of her niece Christina.

She revised it in 2002, after the death of her husband, with the new subtitle Mein Abschied vom traditionellen Christentum, declaring a sevenfold "farewell to traditional Christianity":[8][16]

She wrote: Die Erinnerung an Rudolf Bultmann, den Gelehrten voller Hilfsbereitschaft, den Aufgeklärten voller Frömmigkeit, hat mich durch mein Leben begleitet, als bei mir die Zweifel größer wurden.