Hall opposed coeducation, and one of his main arguments for sex-segregated schools was that it enhanced sexual sublimation and, thus, facilitated social progress:
Sex-segregated schools would hold the sexes apart, not only or simply to allow them to prosper along their natural, dif- ferent gender trajectories, but also as poles on a battery, separated to avoid the inev- itable short circuit, but also because the “hot”, passionate, tingling, erotic sensibil- ities of adolescence, heightened by sepa- ration, created an intense field of force, a kind of adolescent social electricity that was Hall’s designated path to progress. (Graebner, 2006)
In an address before the American Academy of Medicine in 1906, Hall elaborated his opposition to coeducation:
It [coeducation] violates a custom so universal that it seems to express a fun- damental human instinct. … Girls … are attracted to common knowledge which all share, to the conventional, are more influenced by fashions, more imitative and lack the boy’s intense desire to know, be, do something distinctive that devel- ops and emphasizes his individuality. To be thrown on their own personal resources in sports, in the classroom, in nature study and elementary laboratory brings out the best in a boy, but either confuses or strains a girl. (Denmark, 1983)
Hall’s views on women, although widely accepted at the time, did not go unchallenged. For example, Martha Carey Thomas, a feminist and the president of Bryn Mawr College, said, “I had never chanced again upon a book that seemed to me to degrade me in my womanhood as the seventh and seventeenth chapters on women and women’s edu- cation of President G. Stanley Hall’s Adolescence” (Denmark, 1983).