G. Stanley Hall,
Youth: Its Education, Regimen, and Hygiene
“ I have here less to say against coeducation in college, still less in university grades after the maturity which comes at eighteen or twenty has been achieved; but it is high time to ask ourselves whether the theory and practise of identical coeducation, especially in the high school, which has lately been carried to a greater extreme in this country than the rest of the world recognizes, has not brought certain grave dangers, and whether it does not interfere with the natural differentiations seen everywhere else. I recognize, of course, the great argument of economy. ”
