Developmental androgen fluctuations and the five dimensions of mammalian sex (with emphasis upon the behavioral dimension and the human species)

Abstract

Evidence reported largely in the past twenty years is reviewed regarding how mammals are sexually differentiated through variations in circulating levels of a set of biochemicals called androgens. Five fairly distinct dimensions of the sexual differentiation process are identified as follows: the genetic dimension, the genital dimension, the neuro-organization dimension, the nongenital morphological dimension, and the behavioral dimension. The problem of designating a mammal's “overall sex” is briefly discussed. Then, the basic process whereby a “dynamic equilibrium” in androgen levels tends to be maintained within an animal is described, along with an account of the kinds of experiential encounters a mammal can have that can dramatically “upset” the equilibrium. Finally, a “threshold range” concept of androgenic effects upon behavior is discussed, along with an outline of four basic interactive processes whereby behavior apparently can be affected by variations in androgens.