Author Bio: Umm Daud has a degree in Neuroscience from the University of California, Irvine and a degree from the Institute of Knowledge in Arabic and Islamic Sciences.
In recent years, issues pertaining to LGBT persons have become a topic of interest in pop culture, politics, and science alike all over the world. Issues ranging from sexual education in schools, public bathroom usage by LGBT persons, and same sex marriage are all hotly debated. At the heart of the LGBT issue is the question of whether LGBT persons are born that way or they become so because of various social and environmental factors in their life as they grow up. Let us examine this question for homosexuality from the lens of science and see if we can arrive at a conclusion.
There have been numerous genetic studies done to determine whether homosexuality is linked to genetics, making some of us biologically wired to be attracted to the members of our own sex. However most of these studies have been very small, and not conclusive. One of these is the twin study done in 1991 by Bailey and collegues where they interviewed gay men and asked about their identical, fraternal, adoptive and biological brothers to determine if twins are more likely to be gay than non-twin brothers which would implicate genetics as the driver of homosexuality.
Identical twins share 100% of their DNA, so any differences between them must be the result of environmental factors after birth. Fraternal twins are like non twin brothers in that they do not share all of their DNA. They found that a gay man’s identical twin was also gay 52% of the time and his fraternal twin was also gay 22% of the time and his biological non twin brother was also gay 9% of the time and his adoptive brother was also gay 11% of the time (Bailey & Pillard, 1991). The authors surmise that since identical twins in their study had the highest likelihood of sharing sexual orientation (52% compared to 22, 9 and 11%) that there is genetics at play.
However, there are several faults in this study. As you can see, there is a discrepancy in the results, which show that adoptive brothers were more likely than biological non twin brothers to be both gay at the same time (11% compared to 9%). Also, had genetics been at play, identical twins should have shared sexual orientation 100% of the time instead of 52%. The authors fail to account for the similar environment that twins (especially identical twins) have in their home as they grow up which would explain why they are more likely to share sexual orientation.
It is key to note that the twins in this experiment were not separated at birth. They grew up in the same home environment with the same parents. Unfortunately science is not all that objective as most lay people tend to think. Rather, scientists have their own beliefs and agendas at play behind their research and this shows itself in how they sometimes present their findings in a skewed manner to fit with their own agendas. In this case, when Bailey and colleagues presented their findings in the form of a table in their paper, they chose to drop the problematic 9% of non twin biological brothers and instead placed it within a paragraph on the next page such that, from the table it would seem that there is a nice linear correlation between the amount of genetic material brothers share and likelihood of sharing homosexual orientation whereas the case is not so.
In 1993, another similar study was carried out, this time on only 61 pairs of twins (Whitam et al., 1993). In this study, the rates for identical twins were 66% and 30% for fraternal twins. Note that the sample size is extremely small, making it impossible to draw meaningful conclusions and as with the previous study, the twins were not reared apart, rather they grew up together in the same household, making this study riddled with the same problems as the previous one.
A larger study was carried out in 2010 including 7652 twin pairs. This study found that individual environmental factors, meaning factors in the lives of the twins that do not affect the brothers equally, accounted for homosexual behavior twice as much as genetic factors did in men and about 6 times as much in women (Langstrom et al., 2010).
The Search for ‘The Homosexual Gene’
There has also been an effort amongst scientists to hunt for specific genes in the human genome that might code for homosexual behavior. One such study was done in 1993 by Hamer that included 114 families. He saw that the homosexual men in those families tended to have more homosexual relatives on their mother side of the family (Hamer et al., 1993). However his sample size was small and other scientists trying to replicate this finding with a bigger sample size of over 400 families did not find this correlation (Bailey et al., 1999). In the scientific field, any finding that cannot be repeated through similar studies by other scientists is disregarded. Hamer also looked at X chromosomes of 40 gay families and found a location (Xq28) that was similar in gays. However that finding also could not be replicated by other teams (Rice et al., 1999)
In 2017 a team of researchers announced that they had found a gene (SLITRK6) on chromosome 13 that was involved in making someone of homosexual orientation (Sanders et al., 2017) However other scientists in the field dismiss this research as insignificant saying:
“This study is way, way, way too small to draw any meaningful conclusion. None of their findings meets the accepted thresholds for statistical significance in a genome-wide association study (which is why it is published in Scientific Reports). The comments about SLITRK6 and TSHR are utter speculation, and don’t belong anywhere near a modern genetic study—we had decades of such claims that never held up because they didn’t meet statistical significance.” (Jeffrey Barret in a statement for the Science Media Centre).
“The sample size is small, the results have not been replicated in an independent study and the level of evidence presented doesn’t meet the threshold of significance typically required within the field. The press release is appropriate, but I don’t think the work would have been published if it were on a less controversial topic,” agrees Gil McVean of the University of Oxford (Science Media Centre, 2017).
Since all the studies listed thus far are too small to be conclusive on this matter, one might wonder is there then any bigger studies done that could enlighten this issue for us? Indeed, there was recently a big study involving about half a million people that was published in Science Magazine that reports that genetic influences can only explain about 8-25% of nonheterosexual behavior and the 5 locations on the genome thought to be important for homosexual orientation can only explain less than 1% of such behavior (Ganna et al., 2019).
This does not mean that 8-25% of people that engage in homosexual behavior are doing it because of genes, rather it means that on a population level, only 8-25% of homosexual behavior is influenced by genes. According to the authors, a given genome cannot predict whether a person is homosexual or not. Meaning, if scientists were presented with the sequence of DNA of an individual, they would have no way of predicting if the individual to whom the DNA belongs to is homosexual or not. There is no place in the sequence of DNA that could predict a person’s sexual orientation. Thus, homosexual behavior is not highly influenced by genetics.
To explain the concept of heritability of a trait, I will give you the example of hair color and intelligence: 100% of the trait hair color can be explained by genetic influences. Meaning if you look at a population, the variation you see in hair color is all due to genes that encode for the color of hair. However, complex traits such as intelligence are influenced by a number of environmental factors other than genes, such as schooling, nutrition, pollution, disease and etc. and thus have a less heritability percentage. In one population, it has been shown that about 50% of the variation in intelligence in that population could be explained by genetics (Davies, 2011). The other half is due to all the environmental factors that influence intelligence. We can say that hair color is highly heritable and intelligence is less so. The more an environment can influence a trait, the less heritable that trait becomes. Also, high heritability does not mean a sealed fate. Some highly heritable traits can be strongly influenced by environment. For example Phenylketonuria is a highly heritable disease that can be kept in check by simple changes in diet.
The study led by Ganna had another interesting discovery that did not get any media attention: there are statistically significant genetic correlations between homosexual behavior and a number of personality traits: loneliness, openness to experience, having multiple sexual partners, tendency to engage in risky behaviors such as smoking, cannabis use, and mental health disorders such as schizophrenia, major depression, bipolar disorder, and ADHD. This means that people with the listed traits have similar genome to people who are homosexual, granted the genetic effect on homosexual behavior was small to begin with. There was also a negative genetic correlation between subjective well being and homosexuality. Meaning, the genome of people who reported their well being to be good was significantly different than the genome of people who engage in homosexual behavior.
This interesting finding gives a whole new perspective to the link between genes and homosexuality that the study aimed to discover. The team set out to discover the genetic underpinnings of homosexuality, but they ended up actually capturing a genetic profile that might make a person slightly inclined to be reckless and homosexual behavior is really only one of the different kinds of risk taking that individuals engage in such as smoking, cannabis use and having multiple sex partners. The claimed 8-25% genetic influence on homosexuality actually seems like it is a 8-25% genetic influence on risk taking behavior, homosexual behavior being one of them. It just so happened that the main investigation of this study was homosexual behavior and genetics. Had it been something along the lines of, grouping genetically similar individuals, the authors would have seen homosexual behavior next to the risk taking behaviors such as a smoking and consuming cannabis and having multiple sexual partners, indicating these people tend to have slight similarities in their genes. Regarding this, Sathirapongsasuti (one of the co-authors) says:
“I think it’s true we’re capturing part of that risk-taking behavior” in a statement for the Scientific American (Scientific American, 2019).
The team did not see any differences between homosexuals and straight individuals at location Xq28 or in the SLITRK6 gene at chromosome 13 discussed earlier in this paper.
So what do these studies taken all together mean? We can definitely say that homosexuality is not caused by a certain genetic makeup. The most that could be gleaned from all the studies is that certain individuals (due to their genetic makeup) might be more at risk of falling into homosexual behavior when placed under certain environmental factors. Just like alcoholism has been linked to genetics (about half of the risk for alcoholism can be explained by genetics according to National Institute of Alcohol Abuse and Alcoholism) making some members of society more prone to becoming addicted to alcohol if they start drinking, so it seems the case with homosexuality. Certain people might be more prone to becoming homosexual when exposed to certain influences in their lives. Interestingly though, alcoholism is listed as a disorder in the American Psychiatric Association’s Manual of Mental Disorders while homosexuality is not. If people genetically inclined to become alcoholics abstained from tasting any alcohol, they would not fall into this disorder. Yet our society is inundated with messages about LGBT down to public schools where they are being taught there are up to a hundred different sexual identities (BBC, 2020). It is important to note that according to the available research, genes have a much bigger role in alcoholism (50% of the risk of alcoholism is due to genetics) than homosexuality (only 8-25% of homosexual behavior can be explained by genetics).
Brain Anatomy Differences
Some scientists have gone the route of peering into the brains of “homosexual” and “straight” persons to determine if there are any differences between them. Indeed they have found a few places in the brain that differ, such as the corpus callosum (Witelson et al., 2008) and superchiasmatic nucleus (Swaab et al., 1990). However, it is known to all in the neuroscience field that the brain is extremely plastic even in the adult years. Areas of the brain that are frequently used expand, allowing the brain to excel at what it is made to practice. It has been shown for example that London taxi drivers have larger hippocampi, the part of the brain responsible for memory and navigation. It has been demonstrated that their hippocampi grew larger after they started their taxi training, as a result of all memory exercise they did during their training (Woollett & Maguire, 2011). This means that the brain differences between homosexual and straight individuals do not necessarily cause homosexuality, rather they could be the the result of the brain adapting to homosexual thinking and behavior.
Yet other scientists have honed in on the physiological differences between homosexuals and heterosexuals thinking homosexuality is caused by different levels of hormones fetuses are exposed to in the womb. However there is no direct evidence for such hypotheses. Differences such as higher rate of left handedness and smaller ratio of index finger to ring finger have been identified. Often, such differences are blown out of proportion and misunderstood by the public. For example, it has been reported that homosexual men have 82% more likelihood of being left handed than straight individuals (Lippa, 2003). The lay person, not versed in deciphering statistics may think that 82% of the homosexual male population is left handed, significantly more than the straight population. However, this is not the case. One need only to look closer at the actual rates of left handedness within both populations (11.4% in straight men and 19.0% in homosexual men) to realize they are not so different (left handedness occurs in less than 20% of the population in both groups). So the presentation of the data is skewed to place the reader under the impression that the differences are large and definite. There are plenty of right handed homosexuals (in fact majority of them are so) and plenty of left handed straight men. There is no physiological difference that could serve as the definitive criterion to tell whether a person is “homosexual” or “straight.”
Coming to the index finger to ring finger ratio difference that has been found between “homosexual” and “straight” individuals, it has been said that straight women and homosexual men have similar length index and ring fingers while straight men and lesbians have longer ring fingers than index fingers. It was thought that these differences exist because of the differences in exposure to the male and female hormones testosterone and estrogen in the womb. However, a twin study has shown that in identical female twin pairs where one twin is straight and other is homosexual that the homosexual twin tends to have male typical digit ratios (Hall & Love, 2003). This last study proves that homosexuality cannot be caused by genes or prenatal hormone exposure, because identical twins share the same genes and the same prenatal environment in the womb.
Still other physiological differences have been reported such as hair whorl differences between homosexual and straight individuals that have not stood the test of scientific replication, and as such must be disregarded (Rahman et al., 2009).
Much of the research in sexology is not objective as many researchers in the field are themselves LGBT and have personal motivations behind their studies. One of the notable examples is Alfred Kinsey who was the pioneer of sex research and the father of the sexual revolution in the mid 1950s. His reports “Sexual Behavior in the Human Male” and “Sexual Behavior in the Human Female” were wildly popular among the general public of his time as well as in the research community. He revolutionized the way American public viewed and talked about sexuality, yet he was far from being objective in his research. Jones, who did extensive research into Kinsey’s life and authored his biography, writes about him,
“The man I came to know bore no resemblance to the canonical Kinsey. Anything but disinterested, he approached his work with missionary fervor. Kinsey loathed Victorian morality as only a person who had been badly injured by sexual repression could despise it. He was determined to use science to strip human sexuality of its guilt and repression. He wanted to undermine traditional morality, to soften the rules of restraint, and to help people develop positive attitudes toward their sexual needs and desires. Kinsey was a crypto-reformer who spent his every waking hour attempting to change the sexual mores and sex offender laws of the United States” (Jones, 1997).
Kinsey was himself of the “LGBT community” and he was bent on using science to rationalize his own unorthodox sexual desires. From his time until now many of the scientists researching sexuality are from the LGBT community including Dean Hamer who reported on genetic difference between homosexual and straight individuals at Xq28 location of the genome earlier discussed in this article, Simon LeVay who did research on brain differences between homosexual and straight individuals, Anne Fausto-Sterling and more.
The authors of the big genetic study led by Ganna’s team worked with LGBT advocates in writing the research paper as well as presenting the research to the public (Lambert, 2019). This is a clear example of bias. Why should scientists have to work with advocates of anything in presenting their research? Yet they tout this in media as if it were a good thing. Shouldn’t science be free of interference from political and social influences?
Statistics on Homosexual Identity
According to Gallup, numbers of people who identify as LGBT have been rising since 2012, when Gallup first started tracking the measure and the rise is almost completely because of more millenials (those born between 1980-1999) identifying as LGBT. LGBT identity has slightly declined among older generations (Gallup, 2018). This is another indication that LGBT orientation is not biological. Some have argued that the rise is due to more people feeling comfortable with their identity and becoming more willing to embrace their identity due to more social acceptance. This, however, does not explain why the rise in numbers of people willing to identify as LGBT is age specific to the younger generation. Also, younger individuals not only identify themselves as LGBT more often than older individuals do, more of them also report ever having had sexual relations with the opposite sex compared to older individuals (Ganna, 2019). This means that the increased self-reports about LGBT self identity are not due to more people “coming out of the closet” with their identity, but rather a reflection of more younger people engaging in homosexual behavior in recent years.
In accordance with the scientific research available in this field, the American Psychological Association (an organization that wholeheartedly supports homosexual expression and rights of such individuals to get legally married) recognizes that there is not enough evidence to support a biological cause for homosexuality (APA, 2013). With this we look at the flip side of this equation — research on social factors that influence one becoming of homosexual orientation. There is a myriad of research that has found that there is a strong positive correlation between childhood sexual abuse and neglect and homosexual orientation. One way of carrying out such research is a longitudinal study where groups of interest are followed as they age and go through life and see how the factor under research is affecting their life.
In one such study, individuals who experienced abuse in their childhood were identified and followed into adulthood and surveyed at 40 years of age to see how the abuse they experienced reflected in their sexual orientations in adulthood. The researchers found that the incidence of homosexuality was much higher in this group of people who experienced abuse than in a control group of individuals who did not experience any abuse in their childhood (Wilson & Widom, 2010). Another way of carrying out such research is to survey a population of homosexuals and determine what percentage of them had childhood abuse or neglect. In such a study, Schneeberger and collegues found that LGBT populations showed high prevalence of stressful childhood experiences including childhood sexual abuse, childhood physical abuse, childhood emotional abuse, childhood physical neglect, and childhood emotional neglect (Schneeberger et al., 2014).
Homosexual Animals Argument
Proponents of a biological cause for homosexuality argue that incidences of same sex mating in the animal kingdom, ranging from insects to mammals, prove that homosexuality must have biological roots, otherwise it would have existed only among humans and not animals. However, most incidences of same sex mating in the animal kingdom occur because of lack of access to members of the opposite sex. Even in cases where the opposite sex is readily available, scientists have discovered that animals engage in same sex mating for some advantage in their animal societies and even they easily weave between mating with members of their own sex and the opposite sex (BBC, 2015).
“While hundreds of species have been documented doing it [same sex mating] on isolated occasions, only a handful have made it a habitual part of their lives” says Paul Vasey of the University of Lethbridge in Alberta, Canada and that “humans are the only documented case of ‘true’ homosexuality in wild animals” (BBC, 2015).
In the animal kingdom, among chimpanzees, one will find instances of killing one’s own kind, stealing, bullying and the like. Yet such behavior in chimps is never used as a moral justification for murder, theft, and aggression on the basis of a natural biological occurrence. In cases of murder, theft, and aggression, everybody agrees that these are unacceptable behaviors, so why is mating with a member of one’s own sex any different? Since when do people take animal behavior as the criterion to justify if doing something is morally right or wrong? What differentiates us humans from animals that weave between mating with their own sex and the opposite is God’s prohibition about approaching members of our sex, as members of the opposite sex are readily available for marriage to us. God narrates the story of Lot to us in the Quran when Lot said to his people: “Do you commit a shameful deed that no man has ever done before? You lust after men instead of women! You are certainly transgressors.” (Araf 80-81) Unlike animals, we humans are given divine orders and prohibitions that govern our lives. We must live abiding to the limits set upon us by God.
Those who claim that homosexuality is predetermined from birth point to twin studies, genetic studies, studies that have aimed to pinpoint physiological differences between “homosexuals” and “straight” individuals and cases of animal same sex mating to prove that homosexuality has a biological cause. We have analyzed that the twin studies done in this topic are either too small to draw conclusions or they show a significant environmental effect on homosexuality, the only large genetic study in this field discovered a small link between risk taking behavior (one of which is homosexual behavior among other things) and genetics. Correlation does not mean causation, so the existence of physiological differences between homosexuals and straight individuals doesn’t mean that those differences are a manifestation of a biological cause for homosexuality.
In light of all the evidence examined in this paper, the answer to the question, “Is homosexuality predetermined from birth?” is simply “No.” A number of environmental and social factors play a significant role in someone developing homosexual proclivities.
We conclude by cautioning the reader that they must keep in mind that since this is a socially and politically charged topic, the science behind it is influenced by political agendas and biases. In our day and age, many that simply try to claim that homosexuality is not innate are immediately attacked and find themselves at the receiving end of much vitriol, whereas those that argue that homosexuality is caused by biological mechanisms are celebrated, no matter how dodgy their arguments and research. For this reason, any research done in sexology must always be carefully analyzed instead of being accepted at face value.
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Quran. Surah Araf. Verse 80-81