Changes

Development of the reproductive system is a complex process relying on numerous systems and conditions to ensure appropriate structures and rate of development are maintained within the embryo. There are several important criteria that determine appropriate reproductive system development; '''genetic sex''' which determines the sex of the embryo, '''gonadal sex''' and '''phenotypic sex''' which both determine sexual differentiation. Genetic sex determines gonadal sex which in turn determines phenotypic sex. Sex determination relates to the genetic or environmental process which determines the sex of an individual whilst sexual differentiation represents the development of internal and external genitalia.

Development of the reproductive system is a complex process relying on numerous systems and conditions to ensure appropriate structures and rate of development are maintained within the embryo. There are several important criteria that determine appropriate reproductive system development; '''genetic sex''' which determines the sex of the embryo, '''gonadal sex''' and '''phenotypic sex''' which both determine sexual differentiation. Genetic sex determines gonadal sex which in turn determines phenotypic sex. Sex determination relates to the genetic or environmental process which determines the sex of an individual whilst sexual differentiation represents the development of internal and external genitalia.

==Sex Determination in Mammals==

==Sex Determination in Mammals==

In mammals the male is the heterogametic species (XY chromosomes) and females are the homogametic species (XX chromosomes) and this is the first stage in the development of the reproductive system. This stage occurs in the zygote and genes in the Y chromosome regulate the development of gonads towards the male phenotype. Therefore the Y chromosome must be present for the development of the male gender, regardless of the number of X chromosomes (see Developmental Abnormalities section below). Each Y chromosome contains a '''Sex Determining Region''' (SRY) and testes must be present for the formation of male characteristics. Sex hormones produced by the developing gonads affect the further development of the reproductive organs and the nervous system and are therefore crucial.

In mammals the male is the heterogametic species (XY chromosomes) and females are the homogametic species (XX chromosomes) and this is the first stage in the development of the reproductive system. This stage occurs in the zygote and genes in the Y chromosome regulate the development of gonads towards the male phenotype. Therefore the Y chromosome must be present for the development of the male gender, regardless of the number of X chromosomes (see Developmental Abnormalities section below). Each Y chromosome contains a '''Sex Determining Region''' (SRY) and testes must be present for the formation of male characteristics. Sex hormones produced by the developing gonads affect the further development of the reproductive organs and the nervous system and are therefore crucial. For further information in sexual differentation please see [[Sexual_Differentiation_-_Anatomy_%26_Physiology|here]].

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