Homosexuality: Biological or Learned Behavior Axia College of University of Phoenix Homosexuality is at the front lines of the nature versus nurture debate. Many studies have been conducted, but a clear cause has yet to be found. Anti-homosexuals, consisting mainly of religious groups, believe that homosexuality is abnormal, unnatural, and can be changed. Because of their beliefs, homosexuality must be a learned behavior. Whether homosexuality is biological or learned behavior is still a mystery, but scientists are finding more evidence to suggest the former.
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Webster’s online dictionary defines abnormal as deviating from the normal or average. By that definition alone homosexuality is abnormal, but there are other things that are “abnormal” which are acceptable in today’s society. According to the 2000 United States Census Bureau report, 75. 1 percent of Americans are Caucasian. So it is logical to assume the “average” American is Caucasian, but not being Caucasian is not considered abnormal. Minorities have genetic traits that make them different, and it is impossible to change these genetic traits. The same concept holds true for homosexuals.
Homosexuals are a minority because they are biologically different from the majority. So what makes them different? Studies show there is clear a difference between the brains of homosexuals and heterosexuals, and part of it lies within the hypothalamus. The hypothalamus is a small part of the brain that controls sexual behavior, among other things, and it responds to pheromones (Hypothalamus, n. d. ). Several nuclei in the hypothalamus are sexually dimorphic; this includes the interstitial nucleus of the anterior hypothalamus (INAH). The INAH is a nucleus located between the groups of tissue in the anterior hypothalamus.
Although there are four INAH, only the INAH3 is widely accepted as sexually dimorphic (LeVay, 1991). Figure 1 displays the location of the hypothalamus and INAH 1-4, and a size comparison between a heterosexual male and female brain. Figure 1. (A) Location of Hypothalamus and INAH 1-4. (B-D) Shows a size comparison of INAH 1-4 between a heterosexual male and heterosexual female. Allen et al. , 1989 Heterosexual males have a larger INAH3 than heterosexual females. Simon LeVay conducted a study in which he compared the size of the INAH3 between 19 homosexual males, 16 heterosexual males, and six heterosexual females.
LeVay (1991) found that homosexual males have a smaller INAH3 than heterosexual males, and their INAH3 is only slightly larger than the INAH3 of heterosexual females. The study suggests that the cause of homosexuality is located in the brain, but Anti-homosexuals do not agree with his findings. Anti-homosexuals criticize virtually every aspect of his study. They claim that LeVay was biased because of his own sexual orientation, despite him stating: I did not prove that homosexuality is genetic, or find a genetic cause for being gay. I didn’t show that gay men are ‘born that way,’ the most common mistake people make in interpreting my work.
Nor did I locate a gay center in the brain–INAH3 is less likely to be the sole gay nucleus of the brain than part of a chain of nuclei engaged in men and women’s sexual behavior. My work is just a hint in that direction–a spur, I hope, to future work. (Nimmons, 1994, ¶ 4) In their opinion the sample size was too small, and the fact 56. 5 percent of the samples died of Acquired Immune Deficiency Syndrome (AIDS) related complications renders the entire study mute since the disease lowers testosterone, and there is hardly any evidence to suggest that AIDS did not create the differences in size (Chun, 2003).
They also claim LeVay did not properly measure the INAH3. According to Dallas (n. d. ), “His peers in the neuroscientific community cannot agree on whether the INAH3 should be measured by its size/volume or by its number of neurons” (para. 2). It is unclear if behavior can affect the brain structure or if the brain structure affects behavior, so the difference between homosexual men and heterosexual men is not valid (Dallas, para. 3). Lastly, they criticize the fact LeVay could not guarantee the sexuality of his subjects (Dallas, para. 3).
However, this discrepancy probably explains why 17 percent of the group contradicted the study (three heterosexual males had smaller INAH3 while three homosexual males had larger INAH3). In spite of these denigrations, it is clear that homosexuality possibly has a biologic substrate. Just as LeVay found evidence of variation between the heterosexual and homosexual brains so did Swedish scientists Ivanka Savic and Per Lindstro? m. They have produced three incredibly interesting and compelling studies. In the first two studies they documented how males and females of both sexual orientations responded to human pheromones.
The researchers had the test subjects smell four ordinary aromas and male and female hormones while their brains were being scanned with positron emission tomography (PET). Fascinatingly, the normal scents activated the part of the brain which processes smells, but the hormones were processed by the hypothalamus in most. Heterosexual men’s hypothalamus processed the female hormones, but scent area processed the male hormones. The opposite was found for heterosexual females (Schmid, 2006). On the other hand, homosexual males’ hypothalamus responded to males hormones while the scent area processed the female hormones (USATODAY, 2005).
However, the homosexual females processed both hormones in the scent area. Straight men and lesbians found the female hormone more pleasing than the male hormone, and were more likely to be irritated by the male hormones. Straight women found both hormones to be equally pleasing, but were more likely to be irritated by the female hormone (Schmid, 2006). The studies show there is a biological aspect to homosexuality. In addition to the scent studies, Savic and Lindstro? m conducted another brain study in which the researchers found there were more similarities between the brains of heterosexuals and their homosexual counterparts.
They used PET scans and magnetic resonance imaging (MRI) to help document the findings. According to Savic and Lindstro? m (2008): Cerebral responses to putative pheromones and objects of sexual attraction were recently found to differ between homo- and heterosexual subjects. Although this observation may merely mirror perceptional differences, it raises the intriguing question as to whether certain sexually dimorphic features in the brain may differ between individuals of the same sex but different sexual orientation.
We addressed this issue by studying hemispheric asymmetry and functional connectivity, two parameters that in previous publications have shown specific sex differences. …The present study shows sex-atypical cerebral asymmetry and functional connections in homosexual subjects. The results cannot be primarily ascribed to learned effects, and they suggest a linkage to neurobiological entities. (¶1) The study consisted of 25 heterosexual men (HeM), 25 heterosexual women (HeW), 20 homosexual men (HoM), and 20 homosexual women (HoW), for a total of 90 subjects.
HeW and HoM did not show asymmetry in the brain hemispheres, but HeM and HoW did show asymmetry. Figure 2 shows the MRI overlay which illustrates how similar the connectivity pattern is among the different sexual orientations. This study also strongly suggests that homosexuality is biological. Nonetheless, Anti-homosexuals have complaints. As with the LeVay study, they claim that behavior can affect the brain so the studies results do not prove homosexuality is biological, since there is no way to tell if the subjects’ brain changed over time (Wade, 2005). However, the results provide more information about homosexuality.
Figure 2. MRI Scan Results Overlay. Savic ; Lindstrom, 2008 The next controversial study provides a strong case against the unnaturalness of homosexuality. A study by researchers in the Oregon Health and Science University (OHSU) has found sexual orientation in rams is determined by the brain (2004). The researchers discovered group of nerve cells in the medial preoptic area of the anterior hypothalamus (MPOA/AH) of the sheep brain, which they labeled as the ovine sexually dimorphic nucleus (oSDN) (Roselli, Larkin, Resko, Stellflug, ; Stormshak, 2004).
The study also found sheep that prefer female rams have a larger oSDN and the hormone levels drastically differ based on sexual preference (Roselli et al. , 2004). However, Dr. Whitehead argues the mounting of male rams by other male rams is a dominance behavior (NARTH, n. d. ). But the researchers only deemed the male sheep homosexual if they decided to mount a constrained male over a constrained female five out five 10-minute sessions (Roselli et al. , 2004). Dr. Whitehead argues this is because the ram instinctively knows it must subdue the male ram before attempting the mate with the female (NARTH, n. . ). He also claims if the test ram has a poor sense of smell its behavior could be attributed to that. Dr. Whitehead’s last criticism has been mentioned numerous times before; there is no proof that the behavior did not alter the brain. Despite these criticisms, it is evident homosexuality is far from unnatural. The leading reason homosexuality is viewed as a learned behavior is because some people view homosexuality as being unnatural. When the phrase “natural order” is heard, what thoughts come to mind? The average person would think about animals.
Animal behavior is the perfect indicator of what qualifies as natural or unnatural. Animals are not tethered by the bias and ideologies of humankind. Biologists, like Joan Roughgarden, have documented over 450 different species of animals that engage in either homosexual or bisexual behavior (Barber, 2009). Some species, for example, penguins maintain their homosexual pairings for life. Anti-homosexuals proclaim homosexuality is unnatural because it is anti-procreation (Magnan, n. d. ), but how can something so common in the animal kingdom be unnatural?
It was once believed that animals mate only as a means of continuing the species; however, if animals can engage in sexual activity for pleasure why is it a crime against nature for humans to do the same? One must come to the conclusion that homosexuality is natural. Sexual orientation is not a choice, but anti-homosexuals insist that it is and therefore they argue that it can be changed. According to Nevid and Rathus (2005), “Sexual orientation is a statement about romantic or erotic interest and attraction, not sexual behavior” (p. 374).
Simply put, people do not choose who they are attracted to. Anti-homosexuals are correct when they say homosexual behavior is a choice, but why should anyone force himself or herself to do something he or she does not like? Are we the people not entitled to life, liberty, and the pursuit of happiness? This question opens the door to the topic of conversion therapy. Conversion therapy is a controversial subject, and despite what religious groups want people to believe, it is not very successful. Only people who are truly unhappy with themselves benefit from the therapy (Thomas, 1997).
The National Association for Research and Therapy of Homosexuality (NARTH) conducted a two-year conversion therapy study consisting of 860 homosexual subjects. When surveyed, 90 percent of the subjects considered themselves to be predominately homosexual before treatment, but only 33 percent considered themselves to be predominately heterosexual after treatment (Thomas, 1997). In conclusion unwanted homosexual behavior can be changed, but the person’s sexual orientation will remain the same. The sad truth is the person only wants to change so he or she can be accepted by society and not condemned by his or her faith.
Anti-homosexuals have criticisms for every study that remotely suggests homosexuality is biological. They say homosexuality is abnormal, but it is clear there are differences between the brains of heterosexuals and homosexuals of the same gender in humans and animals. It has been documented that over 450 species engage in homosexual or transgendered behavior, yet anti-homosexuals say homosexuality is unnatural. Sexual orientation is not a choice and no amount of therapy can change it. Do not be blinded by anti-homosexuals propaganda.
Despite what you believe, I ask you solely to base whether homosexuality is biological or learned behavior on the science, not religious beliefs or homophobia. References 2000 Census of Population and Housing. (n. d. ). Retrieved August 12, 2009, from www. census. gov/prod/cen2000/dp1/2kh00. pdf Barber, N. (2009, June 17). Gay animals | Psychology Today. Retrieved August 29, 2009, from http://www. psychologytoday. com/blog/the-human-beast/200906/gay-animals Chun, T. (2003). Studies Proving the Biological Origin of Homosexuality Are Flawed. Current Controversies: Homosexuality.
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