In 1838 Sarah wrote a paper called Letters on the Equality of the Sexes and the Condition of Women . It answered many questions which were asked in a letter by a group of ministers who did not like the sisters because they had stepped out of their `` woman 's proper sphere '' . In 1838 Sarah wrote a paper titled Letters on the Equality of the Sexes and the Condition of Women which answered many questions which were asked in a letter by a group of ministers who reprimanded the sisters for stepping out of what the ministers called their `` women 's proper sphere . ''