IS HOMOSEXUALITY GENETIC
It is one of the most explosive topics in society today. The social and political ramifications affect the very roots of this country. But is the country being told the truth concerning homosexuality? Is there really a genetic basis for homosexuality?
Former democratic presidential candidate and Vermont Governor Howard Dean signed a bill legalizing civil unions for homosexuals in Vermont. In defending his actions, he commented: “The overwhelming evidence is that there is a very significant, substantial genetic component to it. From a religious point of view, if God had thought homosexuality is a sin, he would not have created gay people” (as quoted in VandeHei, 2004). Dean is not alone in such thinking.
Most people are familiar with the idea that research has been performed that allegedly supports the existence of a gay gene. However, that idea has been a long time in the making. Almost fifty years ago, the landmark Kinsey report was produced using the sexual histories of thousands of Americans. While that report consisted of a diverse sample, it was not a representative sample of the general population (Kinsey, et al., 1948, 1953). In 1994, Richard Friedman and Jennifer Downey published a review on homosexuality in The New England Journal of Medicine. In reviewing Kinsey’s work, they noted:
Kinsey reported that 8 percent of men and 4 percent of women were exclusively homosexual for a period of at least three years during adulthood. Four percent of men and 2 percent of women were exclusively homosexual after adolescence (1994, 331:923).
With this “statistical information” in hand, some sought to change the way homosexuality was viewed by both the public and the medical community. Prior to 1973, homosexuality appeared in the Diagnostic and Statistical Manual of Mental Disorders (DSM), the official reference book used by the American Psychiatric Association for diagnosing mental disorders in America and throughout much of the rest of the world. Homosexuality was considered a sickness that doctors routinely treated. In 1973, however, it was removed as a sexual disorder, based on the claim that it did not fulfill the “distress and social disability” criteria that were used to define a disorder. Today, there is no mention of homosexuality in the DSM-IV (aside from a section describing gender identity disorder), indicating that individuals with this condition are not suitable candidates for therapy (see American Psychiatric Association, 2000).
Physicians treating patients for homosexuality (to bring about a change in sexual orientation) frequently are reported to ethics committees in an attempt to have them cease. Robert Spitzer lamented:
Several authors have argued that clinicians who attempt to help their clients change their homosexual orientation are violating professional ethical codes by providing a “treatment” that is ineffective, often harmful, and reinforces in their clients the false belief that homosexuality is a disorder and needs treatment (2003, 32:403).
Thus, the stage was set for the appearance of a “gay gene.”
SIMON LEVAY—BRAIN DIFFERENCES
The first “significant” published study that indicated a possible biological role for homosexuality came from Simon LeVay, who was then at the Salk Institute for Biological Studies in San Diego, California. In 1991, Dr. LeVay reported subtle differences between the brains of homosexual and heterosexual men (1991). LeVay measured a particular region of the brain (the interstitial nuclei of the anterior hypothalamus—INAH) in postmortem tissue of three distinct groups: (1) women; (2) men who were presumed to be heterosexual; (3) and homosexual men.
LeVay’s Reported Findings
LeVay reported that clusters of these neurons (INAH) in homosexual men were the same size as clusters in women, both of which were significantly smaller than clusters in heterosexual men. LeVay reported that the nuclei in INAH 3 were “more than twice as large in the heterosexual men as in the women. It was also, however, more than twice as large in the heterosexual men as in the homosexual men” (1991, 253:1034). This difference was interpreted as strong evidence of a biological link to homosexuality. LeVay’s assumption was that homosexual urges can be biologically based—so long as cluster size is accepted as being genetically determined.
Problems with LeVay’s Study
When looking at the methodology of the LeVay study, one of the key problems is that the study has never been reproduced. As William Byne noted, LeVay’s work
has not been replicated, and human neuroanatomical studies of this kind have a very poor track record for reproducibility. Indeed, procedures similar to those LeVay used to identify nuclei have previously led researchers astray (1994, 270:53, emp. added).
Additionally, of nineteen homosexual subjects used in the study, all had died of complications of acquired immunodeficiency syndrome (AIDS). AIDS has been shown to decrease testosterone levels, so it should be expected that those who suffered from that condition would have smaller INAH. Byne continued his comments on LeVay’s work.
His inclusion of a few brains from heterosexual men with AIDS did not adequately address the fact that at the time of death, virtually all men with AIDS have decreased testosterone levels as the result of the disease itself or the side effects of particular treatments. To date, LeVay has examined the brain of only one gay man who did not die of AIDS (270:53).
Furthermore, in a scientific environment where controls and standards are a necessity, LeVay did not possess a complete medical history of the individuals included in his study. He therefore was forced to assume the sexual orientation of the non-AIDS victims as being heterosexual, when some may not have been. In addition, bear in mind that he had no evidence regarding the sexual orientation of the women whose brains he examined. LeVay has admitted:
It’s important to stress what I didn’t find. 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 (as quoted in Byrd, et al., 2001, emp. added).
Many have argued that what LeVay discovered in the brains of those he examined was only a result of prior behavior, not the cause of it. Mark Breedlove, a researcher at the University of California at Berkeley, has demonstrated that sexual behavior has an effect on the brain. In referring to his own research, Breedlove commented: “These findings give us proof for what we theoretically know to be the case—that sexual experience can alter the structure of the brain, just as genes can alter it.... [I]t is possible that differences in sexual behavior cause (rather than are caused by) differences in the brain” (as quoted in Byrd, et al., parenthetical item in orig.). Considering this type of research, it makes sense that a homosexual lifestyle (and/or the AIDS condition) could alter the size of the nuclei LeVay was measuring.
What exactly did LeVay find? In actuality, not much. He did observe slight differences between the groups—if you accept the method he used for measuring the size of the neuron clusters (and some researchers do not). When each individual was considered by himself, there was not a significant difference; only when the individuals involved in the study were considered in groups of homosexuals vs. heterosexuals did differences result. Hubbard and Wald commented on this lack of difference:
Though, on average, the size of the hypothalamic nucleus LeVay considered significant was indeed smaller in the men he identified as homosexual, his published data show that the range of sizes of the individual samples was virtually the same as for the heterosexual men. That is, the area was larger in some of the homosexuals than in many of the heterosexual men, and smaller in some of the heterosexual men than in many of the homosexuals. This means that, though the groups showed some difference as groups, there was no way to tell anything about an individual’s sexual orientation by looking at his hypothalamus (1997, pp. 95-96, emp. added).
Being homosexual himself, it is no surprise that LeVay observed: “...[P]eople who think that gays and lesbians are born that way are more likely to support gay rights.” In a Newsweek article, LeVay was quoted as saying, “I felt if I didn’t find any [difference in the hypothalamuses], I would give up a scientific career altogether” (as quoted in Gelman, et al., 1992, p. 49). Given how (poorly) twisted LeVay’s data are, and his own personal bias, his abandonment of science may have ultimately been of greater service.
Brain Plasticity—A Fact Acknowledged by All Neuroscientists
Today, scientists are keenly aware of the fact that the brain is not as “hard-wired” or permanently fixed as once thought—an important factor that LeVay failed to acknowledge. One of the properties of plastic is flexibility—many containers are made out of plastic so that they will not shatter when dropped. In a similar manner, the brain was once considered to be rigid, like Ball® jars used for canning—but we now know the brain is “plastic” and flexible, and able to reorganize itself. Research has shown that the brain is able to remodel its connections and grow larger, according to the specific areas that are most frequently utilized. Given that we know today that the brain exhibits plasticity, one must ask if the act of living a homosexual lifestyle itself might be responsible for the difference LeVay noted? Commenting on brain plasticity, Shepherd noted:
The inability to generate new neurons might imply that the adult nervous system is a static, “hard-wired” machine. This is far from the truth. Although new neurons cannot be generated, each neuron retains the ability to form new processes and new synaptic connections (1994).
Interestingly, since Shepherd’s textbook was published, additional research has even documented the ability of neurons to be generated within certain areas of the brain. This information must be considered when examining comparative anatomical experiments such as LeVay’s. These cortical rearrangements that occur are not as simple as unplugging a lamp and plugging it into another socket. The changes observed by researchers indicate that if the brain were represented by a home electrical system, then many of the wires within the walls would be pulled out, rewired to different connections in different rooms, new outlets would appear, and some would even carry different voltages. Due to the colossal connectivity that takes place within the brain, any “rewiring” is, by its very nature, going to have an effect on several areas—such as INAH3. Scientists understand these things, yet LeVay’s work is still mentioned as alleged support for the so-called gay gene.
CREDITS : -Dave Miller, Ph.D. Brad Harrub, Ph.D.