by Dan Eden Update: Are Lesbian's Brains Different? New Primate Studies!--Androgens cause brain gender!--A must read. Some interesting facts about being gay: In heterosexual women, the index and ring fingers are usually about the same length. In heterosexual men, the index finger is shorter, on average, than the ring finger. It's one of several differences between the sexes that seem to be set before birth, based on testosterone exposure. About 3 percent of American men and 1.5 percent of women describe themselves as gay or bisexual, according to the National Institutes of Health. Those percentages are three to five times higher among people who have a gay brother or sister. Every older brother a man has increases his chances of being gay. A man with four older brothers is three times more likely to be gay than a man with none. (Blanchard) Lesbians' finger lengths were, on average, more like men's. The same holds true for other traits, like eye-blink patterns and inner-ear function.(Breedlove) 75 percent of young boys who dress up like girls, play with dolls and consistently choose stereotypical female pursuits will grow up to be gay. A similar, though less pronounced, pattern is found in girls who prefer trucks over tea sets. Mothers and aunts of gay men had more offspring than female relatives of heterosexuals. In animal studies, about 8 percent of rams never father offspring because they only have eyes for other males. Australian sheepherders call them "shy breeders." (Roselli). So what's going on here... Since my youth, I have been asking questions and seeking answers. "Why is the sky blue?" "Why do we have to die?" These simple inquiries usually went unanswered and caused a distinct wrinkle in the forehead of my parents; nevertheless, as I grew older and wiser, the answers were available in the form of scientific explanations. As a young adult I began to ask other questions which seemed to allude scientific explanations. One of the most perplexing, for me, was why some people were homosexual. I am not homosexual. I state this not as an excuse or out of fear for being labeled as such. It is simply a fact. But in my nearly fifty years of life I have known many homosexual people and have had many friends who were homosexual-- some secretly and some openly. As a mental health worker in my youth, I counseled many homosexuals and was able to witness the painful humiliation and blatant disrespect that most people afforded individuals who preferred their own gender. It always seemed an oxymoron to call them "gay." Despite their own acceptance of who and what they were, they continued to struggle against the name calling and ridicule that came from even the clergy and so-called "moral" people. One of my closest friends, Michael, once confessed to me that he first "knew" that he was homosexual when he was just ten years old. He vividly recalled watching his mother put on makeup and style her hair in front of her boudoir and later he would play with her clothes. He was not interested with the things that usually amused little boys. When he was older and entered the military service, he became emotionally and physically attracted to a fellow recruit who was openly homosexual. This event validated his suspicions that he was somehow "different" from other males. The fact that such feelings could be cognizant at the age of ten always bothered me. I had been taught that homosexuals made the choice to be such-- or that they were somehow coerced into homosexual identity by an adult at some delicate stage in sexual development. In subsequent conversations with other gay men, I learned that almost everyone had a similar revelation at some point in their early life. Hardly anyone actually made the free choice to be homosexual. In fact, studies confirmed that almost 95 percent of homosexual men were adamant that they were born gay. I learned that there were homosexuals as far back as recorded history. Historians (Gore Vidal in particular) suggested that there has always been, more or less, a constant 10 to 15 percent of males that have preferred their own gender. Once again the question puzzled me: was homosexuality an aberration, an evil choice, a disease-- or could it be a natural phenomenon? While watching a news story on brain research this year, I was surprised to learn that scientists had determined that the characteristics which make us "think" either as males or females was localized in a small portion of the brain called the hypothalamus. Autopsies showed that the relative size and configuration of this master gland is different in males and females. Further research indicated that the hypothalamus in homosexual men was significantly different from that of "straight" (heterosexual) men (see Science, 253: 1034-1037, 1991). To clarify this story, I contacted Dr. Barry Kosofsky, Chief of Neurology at Harvard Medical School's Massachusetts General Hospital in Boston. Doctor Kosofsky [pictured right] warned me that this was a controversial issue and that he would only state what he knew to be true. He wanted it understood that his answers, although enlightening me on the neurological aspects of the hypothalamus, should not be taken as an affirmation of any theories relating to homosexuality. "Fair enough," I said. He then confirmed that my recollection of the scientific bulletin was correct. It does appear that brains, at least the hypothalamus, are gendered. Quickly, I sent him another question regarding embryonic development of the brain. "Is it true that the hypothalamus is formed in the first few weeks of pregnancy?" His response was affirmative, "Most parts of the brain are formed in the first trimester..." (i.e. the first three months of pregnancy). Embryology teaches that early embryos all start out as female. At some point in early gestation, if the chromosomes destine the fetus to be male, this female embryo is altered by the genetically programmed addition of certain hormones, called androgens. These androgens, especially testosterone, instruct the embryo to develop male characteristics. In their absence, the embryo continues to develop into a female. An "XX" pair of chromosomes will yield a female; an "XY" pair will result in a male. The "X" is always contributed from the mother (since she has only "X's"), but the father can contribute either an "X" or a "Y"-- so it is the father's genetic contribution that determines the gender of the child. Homosexual men have "XY" pairs which are typically male in all respects. If all homosexual men have the same chromosomes as heterosexual males, what makes their hypothalamus different? This inquiry received no definitive commitment from my learned friend at Harvard, but he did refer me to some studies where I could find the answer. In a paper published almost a quarter of a century ago, a research psychologist at Villanova University was also puzzled about gender. Dr. Ingebog Ward was studying the sexual behavior of rats, years before the role of the hypothalamus was even suspected of gendering human brains. She divided a group of pregnant rats into three groups. Suspecting that something special might be happening in the early stages of pregnancy, she subjected the first group to stress during the first ten days of gestation by irritating the mother rats to bright lights, noise and annoying vibrations. Ten days in a rat's pregnancy corresponds to the first trimester (3 months) of a human pregnancy. The second group was subjected to stress towards the end of their pregnancy, just before birth. The third group was comprised of male offspring from both prenatal stressed mothers and unstressed mothers. These babies were subjected to the same stress producing stimuli. Dr. Ward then allowed all the males to grow to adulthood without further interference. She then placed each group of males in cages with healthy females to observe if their ability and desire to mate with normal adult females. Here is what happened. "Abstract: Male rats were exposed to prenatal (i.e. before they were born) or postnatal (after they were born) stress, or both. The prenatally stressed males showed low levels of male copulatory behavior and high rates of female lordotic responding. Postnatal stress had no effect. The modifications are attributed to stress-mediated alterations in the ratio of adrenal to gonadal androgens during critical stages of sexual differentiation. Specifically, it appears that stress causes an increase in the weak adrenal androgen, androstendione, from the maternal fetal adrenal cortices, or both, and a concurrent decrease in the potent gonadal androgen, testosterone." Parental Stress Feminizes and Demasculizes the Behavior of Males, Science, January 7, 1972 (83-84). Her findings showed that if a mother is stressed during the early stages of pregnancy, she will release an adrenaline related hormone into her own bloodstream and that of her unborn baby. This hormone, called androstendione, is structurally similar to testosterone, the male hormone. If the baby carries "XY" chromosomes and is destined to become a male, testosterone needs to be active when the Central Nervous System (including the hypothalamus) is being formed. This is the only way that the CNS "knows" to develop along male lines. Because the stress hormone seems to bind to the receptors that would normally be receiving testosterone, there is the delay or blockage of the effectiveness of testosterone, even if it is plentiful. In 1972, Dr. Ward had no idea that androstendione in male pregnancies would prevent or inhibit the hypothalamus to develop into a healthy male brain, but this stress-related hormone now appears to do just that. The brain makes its gender committment very early in development and, once committed to either male or female, it can not change. The interference with testosterone in the later stages of pregnancy, or after birth, does little or nothing to inhibit primary gender development of the other organs of the body. In Doctor Ward's own words: "...The present data support the hypothesis that exposure of pregnant rats to environmental stressors modifies the normal process of sexual behavior differentiation in male fetuses by decreasing functional testosterone and elevating androstenedione levels during prenatal development. During stress conditions plasma testosterone emanating from the gonads decreases while adrenal androstenedione rises. The molecular structure of the two androgens, being very similar, it is postulated that the two hormones compete for the same receptor sites. Since androstenedione is a less potent androgen than testosterone, the decrease in male copulatory ability and increased lordotic potential seen in the prenatally stressed animals of the present study would be expected. The relative difference in potency between testosterone and androstendione has been repeatedly demonstrated.   It is therefore possible that while the body and organs of an animal can be a "male," the brain can coincidentally be "female." This extreme reaction to maternal stress even has a very logical and natural purpose. Sensing that a population is under the stress of crowding or poor living conditions, nature provides this hormonal mechanism as a means to limit population growth and thereby reduce the cause of the stress. Homosexual behavior results in less offspring than heterosexual behavior. Again, in Doctor Ward's own words: "The resulting alterations in sexual behavior provide the basis for an effective population control mechanism, since offspring so affected would not possess the behavioral repertoire necessary to contribute to population growth. Thus, the environment, by triggering an adrenal stress response, may control the reproductive capacity of successive generations of differentiating fetuses and, thereby, population size. "   Rats have been routinely used as psychological models for human brain studies for decades. Although no primate studies have attempted to duplicate this effect, it therefore seems fitting to apply these rodent findings to humans. Prenatal stress in early pregnancy seems to be a rational and plausible explanation for male homosexuality and should be viewed as a natural population limiting phenomenon. Personal choice in homosexuality appears to be an insignificant factor in those offspring who are born with a female hypothalamus, encapsulated in an otherwise normal male body. The social implications of these findings have likely contributed to the lack of primate research or even the replication of Dr. Ward's work with rats. This theory, if accepted at face value, would mean that there are at least three naturally occurring human sexual genders: male, female and homosexual. The problematic explanation (or lack of one) for female homosexuality might well be hidden in some similar biologic mechanism. Remember that the developing female fetus is expecting no prenatal testosterone. This molecule is only supposed to be present if the fetus is male. But androstenedione produced by maternal stress, closely resembles testosterone. Even a small amount of this molecule during the critical first trimester of pregnancy could be enough to make the developing hypothalamus masculine. So the same mechanism can explain both male and female homosexuality. Readers should "google" the famous Dresden Study, conducted after World War II. It sought to prove this theory of stress related homosexuality by evaluating the number of homosexual offspring of women who were in their first trimester of pregnancy during the bombings of Dresden, Germany. The results showed that the percentage of homosexual children during this period was significantly higher. Perhaps modern researchers will want to look at Iraq in future years to see if a similar pattern emerges. Dr. Harry Harlow's famous studies with Rhesus monkeys demonstrated that such things as love and the ability to nurture healthy children was a learned skill that could be altered by post-natal experiences. This non-biologic effect may play a role in female homosexuality and may also be a contributing factor in the degree to which male homosexuality is either expressed or repressed. So another of life's perplexing questions has, for me, been resolved by science. This consistently occurring phenomenon has been labeled everything from a "terrible sin" to a form of mental illness. It should perhaps, in light of the hypothalamus discovery, be viewed as part of the natural variety of human biology. As such, it could be protected from slander by our strong admonitions prohibiting discrimination based on gender or a congenital disaiity. A violation of any human privileges against males with a "feminized hypothalamus" ought to be seen as an affront to basic civil rights. As we evaluate new scientific understanding, antiquated prejudices need to be cast off, letting the functions of nature show us how to live in harmony, to foster compassion to devote our attention to more important moral issues. If you seek the truth, you will eventually find it. And the truth, however elusive, will ultimately set us all free. We ask you to voice your opinion using the comments link at the end of this article.