Sexual Differentiation and its Effects on Sexual Orientation

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Sexual Differentiation and its Effects on Sexual Orientation What controls a human's sexual orientation? The long-standing debate of nature versus nurture can be extended to explaining human sexual orientation. Is it biological or environmental? The biological explanation has been gaining popularity amongst the scientific community although it is only based on speculations. It is argued that sexual orientation is linked to factors that occur during sexual differentiation. The prenatal exposure to androgens and their affect on the development of the human brain play a pivotal role in sexual orientation (2). Heredity is also part of the debate. Does biology merely provide the slate of neural circuitry upon which sexual orientation is inscribed? Do biological factors directly wire the brain so that it will support a particular orientation? Or do biological factors influence sexual orientation only indirectly? Gender is determined by the sex chromosomes, XX produces a female, and XY produces a male. Males are produced by the action of the SRY gene on the Y chromosome, which contains the code necessary to cause the indifferent gonads to develop as testes (1). In turn the testes secrete two kinds of hormones, the anti-Mullerian hormone and testosterone, which instruct the body to develop in a masculine fashion (1). The presence of androgens during the development of the embryo results in a male while their absence results by default in a female. Hence the dictum "Nature's impulse is to create a female" (1). The genetic sex (whether the individual is XX or XY) determines the gonadal sex (whether there are ovaries or testis), which through hormonal secretions determines the phenotypic sex. Sexual differentiation is not drive... ... middle of paper ... ...ally factors are responsible for sexual orientation. There are so many variations within society that could affect at person's sexuality, that it is impossible to make any assertions at this point. Therefore the nature and nurture debate is still open. Works Cited: 1) Carlson, Niel R. Physiology of Behavior. 7Th ed. Massachusetts: Allyn and Bacon, 2001. 2) Swaab, D.F., and Hofman, M. Sexual Differentiation of the Human Hypothalamus in Relation to Gender and Sexual Orientation. Trends in Neuroscience. 18, 264-270. 3) Breedlove, M.S. Sexual Differnetiation of the Brain and Behavior. In Becker, J.B, Breedlove, S.M, and Crews, D. (EDS). Behavioral Endocrinology. Pp 39-70. 4) Money, J. , Schwartz, M. and Lewis, V.G. Adult Erotusexual status and Fetal Hormonal Masculinization and Demasculinization:46, XX. Psychoneuroendocrinology, 1984, 9, 903-908.

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