Neural Mechanisms of Sexual Behavior - Research Paper Example

? Neural Mechanisms of Sexual Behavior William Monk North Central The definition of female and male is a complex issue primarily because there are so many perspectives regarding gender, majority of which draw from cultural and social values. Biologically, there are numerous factors to consider prior to determining the gender of an individual. Some of the common methods of determining human gender and sex include anatomical features such as testes, ovaries, and genital organs, physiological description of the interaction and functions of anatomical features, chromosomal makeup, genetic makeup, gender identity, and gender role behaviors. However, these methods of sex-determination are not comprehensive enough to assign an individual a sex status. For instance, some anatomical features are not consistent with the chromosomal makeup of an individual, such as facial hair in XX chromosome females (MacKay, 2008). The adoption of female gender-determination tests in international competitions resulted from increased awareness of athletes using performance-enhancement drugs to attain a “masculine advantage” over the other athletes. Moreover, organizers of international competitions were suspicious that some female athletes from Soviet and Germany were not really “women”. After the Cold War, the mistrust between western nations and the eastern bloc perpetuated the concerns. Consequent reassignment surgeries for former Olympic athletes and the revelation of a German athlete with a record in women’s high jump in the early 1900s as a male with hermaphroditic characteristics fuelled the controversy. International Amateur Athletics Federation and the International Olympic Committee implemented policies that stipulated the testing of female athletes to determine their “femininity” and disqualify participants perceived to have male advantage (Elsas, 2009). The initial gender-determination tests included parading athletes naked before a panel of judges who performed gynecological examinations. Sex chromatin testing (Barr test) replaced the naked parades, generally looking for an inactive second x chromosome present in female cells. Sex-determining Region Y (SRY) analysis soon succeeded the Barr test, testing the presence of an important gene in male development (Willard, 2001). Nonetheless, the officials expressed dissatisfaction with complexities of sex-determination tests, as non-typical femininity did not necessarily mean that an athlete was male, which led IOC to abolish sex-determination tests on competing athletes prior to the 2000 Olympics. Based on the findings of the study of “Jane Doe” from the Howard Hughes Medical Institute, this paper presents a case study on sex determination of one female athlete. This particular case uses Jane Doe as the study subject, a successful athlete participating in the United Earth Games. Jane Doe is 20 years old, weighs 110 pounds and 5 feet 8 inches in height. Jane is single but currently engaged. A physical examination of the subject shows that Jane’s female external genitalia are present and well formed. Female secondary sex characteristics show that she has no facial hair or chest, but breasts are present. Additionally, Jane has sparse public and underarm hair. On medical examination, the subject highlights a problem with menstruation, a common characteristic among female athletes due to the rigorous training (Elsas, 2009). The subject passed all other tests. However, the subject discussed her worries over marriage, citing that her aunt was not able to get pregnant and expressed her fears of such occurrences running through the family lineage. At this stage, determining her sex is impossible despite the female physical characteristics, as there might be another complex explanation for the menstruation problem. The next sex-determining test is karyoptype. Biological facts indicate that a human has 46 chromosomes. These chromosomes carry the dictating instructions that influence sex-specific traits. There are two sex chromosomes, X and Y. Typically; women have an XX sex-chromosome pair, while men have an XY pair (Willard, 2001). According to scientists, the presence of a Y chromosome reflects male traits, thus a look at the karyotype may assist in determining the sex of an athlete. A karyotype is a snapshot arrangement of all chromosomes in a particular cell. After performing the necessary procedures on the blood sample, the kayrotype of the athlete seems similar to that of a normal male. However, her physical appearance identifies her as a female. Thus, the problem is to declare the athlete as a male based on the presence of the Y chromosome, or label her as a female yet she posses a Y chromosome. At this point, it is important to discuss the development of male humans. The point in time at which the human embryo begins to differentiate into female or male is seven weeks after fertilization. Scientists consider the window period in between as bi-potential, as the gonads have not developed to ovaries or testes, and the Wolffian duct (which develops to become the male epididymis, vas deferens, and vesicles) and the Mullerian duct (develops to become the uterus and fallopian tubes) are present (MacKay, 2008). Meanwhile, the embryo waits for differentiation instructions contained in the DNA. In normal circumstances, the Y chromosome carries the differentiation signal to an embryo to initiate development of becoming a male. The gene responsible for initiating these events is SRY, which occurs in the Y chromosome’s shorter arm. Scientists call the SRY “testis-determining factor” as it is responsible for transforming the gonads into testes. However, the SRY does not incorporate all the instructions necessary for male development, but it contains codes for the transcription factor, which subsequently turns genes on or off thus controlling their expression. Consequently, the testes producemale hormones that work towards the development of a male.The testes incorporate few specific cell types, including Sertoli cells and Leydig cells. The latter produces testosterone, an important androgen responsible for initiating production of the epididymis, vas deferens, and seminal vesicles. On the other hand, Sertoli cells initiate production of Mullerian inhibitory factor, whose primary responsibility is the destruction of ancestral tissue of the uterus and the fallopian tubes (MacKay, 2008). Considering the implication that SRY has over male development, it is therefore important to determine whether our subject has a phenotype of a “woman” as there is no evidence of a functional SRY gene. Indeed, some form of mutation may have affected the SRY gene, thus affecting its operation significantly (Simpson, 2000). Determining the gender of the athlete is still a problem, as the events leading to the complete development of a male depend on many other gene and protein activation. Consequently, this would hinder the development of a male. Thus, there may be a possibility of interruption along the process line. This study uses the polymerase chain reaction (PCR) method to determine the functionality of the SRY gene on her Y chromosome. This method amplifies a specific DNA sequence. It incorporates mixing a DNA sample with a single-stranded nucleotides sequence (primer) capable of identifying a short and specific DNA sequence outside the boundaries of the gene of interest. However,there has to be two different primers as the DNA molecule has two complementary strands (Schafer and Goodfellow, 2007). The DNA sequence samples undergo flanking by the two primers on both the DNA strands. After identification of the start regions, copies of the segment are made by adding DNA polymerase. This process begins all over again, until about 30 cycles. This results in plenty of DNA sample for sequence analysis. Among the three sex-determination tests, the PCR and karyotype test indicate that Jane is a male, while the physical exam favors her femininity. The athlete has a complete androgen insensitivity syndrome (CAIS), a rare form of male pseudohermaphroditism that affects one in every 20,000 infants. Individuals having both male and female gonad tissues (testes and ovaries) are true hermaphrodites (Simpson, 2000). On the other hand, pseudo-hermaphrodites have gonad tissue of one sex, though there is ambiguity in external genitalia. An explanation to Jane Doe’s case is that the functional SRY triggered her development as a male, although interruptions occurred along the way, resulting to incomplete development of male characteristics. Individuals like Jane Doe who display the CAIS syndrome have the typical male chromosome pair, XY. However, some form of genetic mutation occurs in instructions that dictate to specific cell receptors, resulting to incomplete development of male physical characteristics (Schafer and Goodfellow, 2007). This is because the defective cell receptor does not recognize androgen-steroid hormones responsible for primary and secondary development of sex characteristics of males. Thus, all cells lack functional androgen receptors, and tend to behave as though testosterone hormones are absent. This condition is similar to what happens in the development of normal females. Based on the results, this case study qualifies Jane Doe to compete in United Earth Games based on medical and scientific world principles. References Elsas, L.J. (2009). Gender verification of female athletes. Genetics in Medicine 2(4):249–54. MacKay, S. (2008). Gonadal development in mammals at the cellular and molecular levels. International Review of Cytology 200:47–99. Schafer, A. J., and Goodfellow, P. N. (2007). Sex determination in humans. BioEssays 18(12):955–63. Simpson, J.L. (2000). Genetics of sexual differentiation. In: Carpenter, S.K., and Rock, J.A., eds. Pediatric and Adolescent Gynecology. Second ed. Philadelphia: Lippincott Williams & Wilkins, 2000; 1–41. Willard, H. F. (2001). Clinical Cytogenetics: disorders of the autosomes and the sex chromosomes. In: Nussbaum, R.L., McInnes, R.R., and Willard, H.F., eds. Genetics in Medicine. 6th ed. New York: Saunders. Read More