Sex Endocrines in Development and Prepuberal Life1

Abstract

A large literature that bears upon the problem of the role of sex hormones on sexual differentiation is evaluated. The application of the hormone theory to the control of the differentiation of the reproductive system in embryos is brought into question and support is given to the thesis that differentiation of the reproductive system rests upon a genetic factor basis that operates without the intervention of hormones secreted by the gonads. Evidence is presented to indicate that differentiating gonads are incapable of secreting hormones until periods much later in development than proper disposition of the 2 sets of embryonic sex ducts. The application of chemical hormones to developing mammal embryos, although inducing sexual modification, does not produce results that are interpretable on the current theory of hormonal control over development of the reproductive system; and gonadectomy (in the opossum pouch young), which would remove all possible sources for gonad-secreted hormones, is followed by characteristic differentiation of a [male] or [female] reproductive system appropriate to the genetically detd. sex. The differentiation of the duct systems, therefore, does not depend upon such hormones.