A person's sex can be considered across various levels. To illustrate, genes, hormones, and genitalia can all be considered physical markers of a person's sex. In addition to physical markers, behaviors such as gender role, gender identity and sexual orientation can be perceived as stereotypically male or female. The purpose of this review is to summarize current knowledge of sexual differentia...

The 20th-century theory of mammalian sex determination states that the embryo is sexually indifferent until the differentiation of gonads, after which sex differences in phenotype are caused by the differential effects of gonadal hormones. However, this theory is inadequate because some sex differences precede differentiation of the gonads and/or are determined by non-gonadal effects of the sex...

Sex differentiation process, determination of sexual strategy, and gametogenesis of the annual fish Austrolebias charrua are established. Evidence of histological sex differentiation in an antero-posterior gradient was observed in pre-hatching stages. Sexual strategy corresponds to the "differentiated gonochoric" pattern. Histological analyses of adult gonads showed an asynchronous spawning mod...

In order to learn more about the role of sex chromosome-dependent gene products in gonadogenesis, changes in protein patterns were studied during gonadal development. Two-dimensional gel electrophoresis analysis revealed specific proteins in both sexes at all developmental stages. Evidently the gonads are not indifferent by biochemical criteria at any developmental stage and express several spe...

Sex Determination and Differentiation in Vertebrates Umesh Rai and Brototi Roy Department of Zoology, University of Delhi Delhi-110007 The concept of sex determination and differentiation has been baffling mankind since time immemorial. While Aristotle hypothesized in 335 B.C. that sex was determined by the heat generated during conception, Andreas Vesalius in 1543 A.D illustrated that women we...

It was the aim of this study to characterize development gonads and genital ducts in equine fetus around time sexual differentiation. This included identification localization primordial germ cell population. Equine fetuses between 45 60 days gestation were evaluated using a combination micro-computed tomography scanning, immunohistochemistry, multiplex immunofluorescence. Fetal increased size ...

The genetics of sex determination is a child of the twentieth century, which overturned the previously held view that sex was determined by the environment. The last quarter of the century witnessed an active search for sex-determining genes in mammals. Although successful, the modus operandi of these genes remained unknown, and the relationship between the sex-determining systems of mammals an...

The determination of a baby’s sex begins at the chromosomal level with the insemination of the ovum. Further sexual differentiation follows during the subsequent embryogenesis. However, chromosomal anomalies, gene mutations, and other exogenous or endogenous factors can cause disorders of sexual differentiation. These disorders manifest during childhood or at the latest in puberty, making patie...

The determination of a baby’s sex begins at the chromosomal level with the insemination of the ovum. Further sexual differentiation follows during the subsequent embryogenesis. However, chromosomal anomalies, gene mutations, and other exogenous or endogenous factors can cause disorders of sexual differentiation. These disorders manifest during childhood or at the latest in puberty, making patie...