Recently, in western society sexual orientation has been a large topic of discussion. Kauth and Kalichman (1995) defined sexual orientation as “the cumulative experience and interaction of erotic fantasy, romantic-emotional feelings, and sexual behavior directed toward one or both genders” (p. 82, as cited in Wilkinson & Roys, 2005, p. 66). Yet, questions arise with regards to the etiology of sexual orientation, which prompted the investigation of the question: What factors influence sexual orientation in men and women? This paper aims to explore the genetic, hormonal and social factors that may contribute to the development of one’s sexual orientation, followed by a conclusion that summarizes the critical points that were discussed in the paper.
Genetic Influence
Genetic factors were a popularized notion when explaining sexual orientation, yet studies concluded that genetic evidence was “inconclusive at best” (Bearman & Bru ̈ckner, 2002, p. 1180). For instance, a study conducted by Hamer, Magnuson, Hu and Pattatucchi (1993) allegedly associated an “X-linked gene at position Xq28” as the culprit responsible for homosexuality amongst males (p. 1186, as cited in Bearman & Bru ̈ckner, p. 1186). Yet, a recent study conducted by Rice, George, Anderson, Risch, and Eberis (1999) was unable to replicate their findings (p. 1186, as cited in Bearman & Bru ̈ckner, p. 1186). Therefore, if a gene responsible for one’s sexual orientation does exist, it should exist elsewhere on the chromosome (Bearman & Bru ̈ckner, p. 1186).
Furthermore, some past studies compared the “monozygotic (MZ) twins’ concordance” for homosexuality with the likelihood of homosexuality in dizygotic (DZ) twins (Bearman & Bru ̈ckner, 2002, p. 1184). Most of the family studies indicated an increased prevalence in homosexuals amongst MZ twins as opposed to DZ twins (Bearman, & Bru ̈ckner, p.1184). However, the recent study conducted by Bearman, & Bru ̈ckner reported there to be only a 6.7% concordance amongst the MZ twins, and a 7.2 % concordance amongst the DZ, who has less genetic similarity than MZ (p. 1197). Although both sides of the argument were presented, the recent study utilized a big sample pool to collect the data, which was indicative of more reliable report (Bearman, & Bru ̈ckner, p. 1184). Yet, additional research would be required before genetic factors can be removed from of the argument.
Hormonal Influence
A prominent hormonal study associated homosexuality to the extreme exposure to prenatal androgens during pregnancy (Berenbaum & Hines, 1992, as cited in Bailey, Bechtold, & Berenbaum, 2002, p. 334). It was believed that this would slow the developmental process of the left hemisphere, leading to “anomalous dominance”, associated with non-righthandedness (Geschwind & Bryden, 1985, as cited in Mustanski, Bailey, & Kaspar, 2002, p. 114). Increase or decrease in non-right handedness was a potential indication of homosexuality in females and males respectively (Mustanski et al, p. 115). Similarly, a study by Mustanski et al., indicated that non-right handedness correlated to female homosexuality, yet nothing significant was observed for males, suggesting that sexual-orientation was at “least partly inborn” (p. 118).
Even with the presented evidence the precise developmental time period in which sexual orientation may be programmed into ones’ “neural circuitry” remains to be found (Mustanski et al, 2002, p. 113). Nevertheless, the general agreement was that “biology plays an important role in the development of male and female sexual orientation” (Hershberger, 1990, p. 43, as cited in Bearman & Bru ̈ckner, 2002, p. 1180).
Social Influence
Majority of the information regarding the “etiology of adult homosexuality” were obtained from the self-reported stories of “self-identified homosexuals” (Bearman & Bru ̈ckner, 2002, p. 1200). With this, Bearman & Bru ̈ckner reported that the critical factor affecting sexual-orientation was the opportunities (social component) that enabled for “early same-sex romantic attraction” (p.1200). For instance, it was indicated that male opposite-sex (OS) twins were “twice as likely” to be attracted to the same sex, because of a less gendered upbringing, that increased the likelihood of male same-sex preferences (Bearman & Bru ̈ckner, 2002, p. 1181).
Furthermore, it has been observed that parent’s social bias for heterosexuality has been instrumental in discouraging homosexuality and enforcing behaviour observed in “gendered socialization scripts” (ie: stereotypically how men and women should behave) (Huston, 1983, as cited by Bearman & Bru ̈ckner, 2002, p. 1182). Likewise, developmental studies found that boys were more likely to become excluded for “preferring female-type toys or games” (Bearman & Bru ̈ckner, p. 1182). Conversely, tomboys were more commonly accepted by both sexes and were not a strong predictor of homosexuality (Bailey et al., 2002. p. 335).
Similar trends were observed with the addition of an extra variable, religion, a factor that affected one’s socialization. Wilkinson and Roys’s (2005) study supported the notion that as religiosity increased in heterosexuals, their attitudes towards homosexual males had a more negative behavioural connotation than females (p. 72). Wilkinson and Roys’s believed that the results were tied to the beliefs of conservative Christianity, which places a greater focus on the repression of male homosexual urges (behaviours), while giving less attention to addressing homosexuality in females (p. 79) Although, the specific mechanisms in which socialization impacts individuals’ sexual preferences have been “poorly specified”, further research would be necessary (Bearman & Bru ̈ckner, 2002, p. 1182)
Conclusion
Numerous factors (genetic, hormonal, and social) came into play when determining the etiology of sexual orientation. However, much of these components contained a lot of contradictory evidence and uncertainty, regarding the extent they influenced one’s orientation, especially within genetics. Regardless, some crucial points would be that non-handedness was related to an increase in homosexuality in females, less gendered upbringing increased the likelihood of homosexuality in OS male twins, and opportunity can be a critical component during the development of sexual orientation (Mustanski et al, 2002, p. 118; Bearman & Bru ̈ckner, 2002, p. 1181). Additionally, much of the evidence was generated from correlational studies, which does not necessarily translate to a causal relationship. Therefore, scientists continue to reiterate that “neither genes, nor hormones, nor specific social situations, determine sexual behavior by themselves” (Bearman & Bru ̈ckner, p. 1181). Instead, it should be an interplay of all these factors.