Abnormal Sexuality in Animals. III. Sex Reversal

Abstract

A literature review. Cases are classified due to: (1) quantitative disharmony between [male] and [female] genetic sex-differentiating reactions. (2) Overriding of genotype by disturbance of general physiology of the zygote by changing the metabolic level in: (a) ovum before fertilization; (b) embryo, by hormone, by general metabolic or other change; (c) post-embryonic life, by altered nutrition, castration, gonad grafts, abdominal tuberculosis, etc. Possibility and direction of sex-reversal, its conditioning factors and effects on sex of offspring are discussed. It is suggested that production of ovarian or testicular tissue in any gonad is conditioned not by local tissue differences but in the environment during development; phenotypic sex-reversal does not affect the genotypic sex of an individual; form or function of a gamete is determined, not by its chromosome content, but by the functioning of the gonad producing it; genes condition one or other type of initial metabolism and thus determine sex; in species with sex-reversal usually the genotypic physiological state is readily over-ridden by environmental agencies and sex-reversal is an adaptive response to changing environment.