Biological Research on Homosexuality Misleads Public

by Dr. Jeffrey Burke Satinover

Excerpted from the book, Homosexuality and American Public Life, which provides a comprehensive review of the biological research on homosexuality.

It is important to note that serious research on the biology, innateness, or genetic determinants of homosexuality has only just recently begun. In contrast to what the public is being led to believe, the research that has been done thus far suggests that genetic factors account for, at most, a small proportion of the risk. J. M. Bailey and R. C. Pillard, two of the researchers most widely cited as having demonstrated that "homosexuality is genetic," were forced to admit otherwise by the results of their own research.

Neuroanatomic research

In 1991, newspapers primarily from west and east coasts trumpeted the discovery of a brain difference between homosexuals and heterosexuals. Although the research finding itself was reported with relative accuracy, the accounts universally concluded that the discovery had social-policy implications. Commentators triumphantly claimed that the discovery would halt any remaining uncertainty that homosexuality was either a choices, or a consequence of factors in upbringing. Therefore, they claimed, to continue supporting anything less than full acceptance of homosexual behavior would be proof positive of prejudicial hatred.

What precipitated this outpouring? In August of 1991, a San Francisco neuroanatomist, Simon LeVay, published an article in the respected journal, Science. It reported his finding that a localized cluster ("nucleus") of cells in the brains of "homosexual" men was twice as large, by volume during autopsy, as in "heterosexual" men.¹ "Homosexual" and "heterosexual" are in quotations here because in this particular study the definitions of each were extremely ambiguous and there was no way of verifying sexual orientation, as the subjects were dead.

But this was not the first such discovery. In 1989, a year prior to a group reported in Brain Research that they had found a similar difference in both volume and number of cells in a different brain nucleus.² The media did not report this first study because Brain Research, unlike Science, is read only by neuroscientists. And, in contrast to journalists, the neuroscientists themselves genuinely understood the research and its limitations, and seeing no reason to make grand pronouncements.

More recently, an additional difference in another part of the brain was reported, also in the Proceedings of the National Academy of Science of the United States of America. This study claimed that a difference between male homosexuals and heterosexuals was found in the anterior commissure, a structure that divides the left and right halves of the brain. The authors found that the anterior commissure was larger in women and homosexual men than in heterosexual men. This was a grouped statistical difference; however, the size of the anterior commissure in 27 of the 30 homosexual men actually fell within the range of sizes found among the 30 heterosexual men. As did LeVay, these authors also used brain samples obtained preponderantly from men who died of AIDS, introducing a substantial variable into their work.³

The only other study to examine morphological differences in the anterior commissure—published in 1988 and not mentioned by the press—found, in part, precisely the opposite. Namely it found that the anterior commissure was larger in men than in women.⁴

The brain's structure changes with use
To a certain degree, detection of brain differences is on a par with the discovery that athletes have bigger muscles than nonathletes. Though a genetic tendency toward larger muscles may somewhat predispose a person to become involved in athletics, becoming an athlete will also build bigger muscles.

The layperson, reinforced by media, is apt to assume that brain differences must be innate and unchangeable, especially differences in the number of cells as contrasted with the simple volume occupied by a collection of cells. We tend to think of the mind as "software" and the brain as "hardware"--the former plastic and changeable, the latter fixed at birth. To an extent, this analogy can be embraced, but the analogy breaks down at a certain point. Various processes go on throughout life: the selective death of brain cells in response to training or trauma, the establishment of new connections between cells, dramatic increases or decreases in the "thickness" of connections between cells as a result of learning, the loss of interneuronal connections through "pruning."

Unlike our modern computers, the brain's software is its hardware. We know from animal studies that early experience, and especially traumatic experience (this has special pertinence with respect to the childhood histories of male homosexuals as we will discuss later), alters the brain and body in measurable ways. Thus infant monkeys, who are repeatedly and traumatically separated from their mothers, suffer more or less permanent alterations in both blood chemistry and brain function.⁵

A similar piece of research on homosexuals with an indeterminate meaning is the recent finding of a protein—an Alpha1-Antitrypsin variant—in the blood of homosexual men, but not heterosexual men. Again, we have no way of determining whether this is an innate or an acquired difference, or whether it is even replicable.⁶ There is a current theory about the developmental causes of depression and the interaction of genetics with development. It claims that under conditions of early trauma, a genetically based susceptibility to stress creates a greater vulnerability to intense stress-responses later in life.⁷

This "vulnerability" is represented physiologically as measurable alterations in the brain. Components of "stress" depend on one's subjective interpretation of events. The brains in individuals with the same genetically determined biology may respond quite differently. One may demonstrate no brain changes, while another may demonstrate very significant changes.⁸

Some lifestyle-induced brain changes
Likewise, in individuals who became blind as adults and learn Braille, the part of the brain governing the right index finger became progressively enlarged. Just this year, researchers reported measurable increases in brain tissue associated with learned sexual activity in rats.⁹

The editor of Nature commented on the LeVay research:
Plainly, the neural correlates of genetically determined gender are plastic at a sufficiently early stage...Plastic structures in the hypothalamus allowing the consequences of early sexual arousal to be made permanent might suit [those who claim an environmental origin to homosexuality] well.¹⁰

And, of course, all this presumes that the research itself is legitimate and accurate. Was it? No. Writing in Technology Review, published at the Massachusetts Institute of Technology, two prominent geneticists commented on the quality of the LeVay research. Paul Billings and Jonathan Beckwith write: LeVay "could not really be certain about his subject's sexual preferences, since they were dead."¹¹

His "research design and subject sample did not allow others to determine whether it was sexual behavior, drug use, or disease history that was correlated with the observed differences among the subjects' brains."¹²LeVay's method of defining homosexuality was more likely to "create inaccurate or inconsistent study groups."¹³

The prevalence of childhood sexual abuse amongst homosexuals
Childhood trauma has terrible effects on the emotional well-being of adults. Many studies demonstrate the sadly disproportionate extent of sexual abuse in the childhoods of homosexual men.

From May 1989 through April 1990, 1,001 adult homosexual and bisexual men attending sexually transmitted disease clinics were interviewed regarding potentially abusive sexual contacts during childhood and adolescence. Thirty-seven percent of participants reported they had been encouraged or forced to have sexual contact before age 19 with an older or more powerful partner, of which 94 percent occurred with men. Median age of the participant at first contact was 10; median age difference between partners was 11 years. Fifty-one percent involved use of force; 33 percent involved anal sex. Black and Hispanic men were more likely than white men to report such sexual contact. Using developmentally based criteria to define sexual abuse, 93 percent of participants reporting sexual contact with an older or more powerful partner were classified as sexually abused. Our data suggest the risk of sexual abuse may be high among some male youth.¹⁴

The same is true for pedophiles:
The association between perpetration of sexual abuse and the offender's own victimization as a child has been well documented in the literature. Various researchers have examined this relationship by assessing the exclusiveness of the sexual abuser's behavior, the gender of his victims and the gender of his own childhood abuser. Subjects were 135 pedophiles...who admitted to their offenses. A total of 42 percent of pedophiles...reported being sexually victimized in their own childhoods...[and] appear to choose their age-specific victims in accordance with the age of their own experience of sexual victimization. Although the cause of child molestation remains undetermined, these results support social-learning and modeling theories.¹⁵

Dr. Satinover, M.D., is a diplomat of the American Board of Psychiatry and Neurology and the C.G. Jung Institute of Zurich, Switzerland. He has authored several books, including Homosexuality and the Politics of Truth. He is a member of NARTH's Scientific Advisory Board (National Association for Research and Therapy of Homosexuality). This excerpt is edited by Melissa Fryrear and Chad Hills and reprinted with permission.

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