As the facts concerned with child development become collaborated into a more exact and unified body of scientific knowledge, it will become easier to understand tendencies to perversion from the normal that may appear at any point in the child's developmental progress. The ultimate attainment of normality in the adult depends on two great factors: (1) Hereditary and congenital anatomic and physiologic foundations; and the persistence of the normality of these congenital foundations during the period of (2) the physiologic processes of development. The foundations concern matters of physical structure and organization of all organs, including brain and nervous system, and concern the sexual organization, whether male or female. But also the physiologic processes of development must take hold of these anatomic and physiologic foundations and modify and advance them safely to final matured conditions and processes according to developmental laws.
In the course of this upward road, however, lie