Note 423 — Chapter III · THEORY OF THE ORIGINAL PAIRING OR MONOGAMOUS FAMILY
Reading edition
Compare Geddes and Thompson, Evolution of Sex, 32-54, who discuss the literature relating to sex-determination; and Geddes, article "Sex" in Encycl. Brit. See the bibliographies of the subject in Geddes and Thompson, op. cit., 40, 53, 54. Marshall, A Phrenologist amongst the Todas, 110, 111, regards the tendency to produce more males than females as due to natural selection, practiced by an in-and-in breeding people, made necessary originally by female infanticide. Thus a "male-producing variety of man is formed."