|Evolution in the News - October 2021|
|by Do-While Jones|
Evolutionists have a new explanation for how homosexuality evolved.
Homosexuality has puzzled evolutionists for decades. The book, Understanding Homosexuality: Its Biological and Psychological Bases, edited by J. A. Loraine, was published in 1975. 1 That was the first reference we found that attempted to address the question as to whether homosexuality is genetic, or a learned behavior. The problem for evolutionists is, if it is genetic, how could it have evolved, and why wasn’t it immediately eliminated from the gene pool by natural selection? Inquiring minds want to know!
The number of children you have is inherited. If your parents didn’t have any children, you won’t have any children either. All kidding aside, it is a serious problem for evolutionists.
Evolutionists believe all biological characteristics evolved through a natural process—specifically, random variation filtered by natural selection. The Darwinian assumption is that because not every individual of a species is identical, and because there are times when there are insufficient resources to support the entire population of a species, those individuals who have differences which make them better able to survive to maturity and reproduce will become the dominant sector of the population, which drives to extinction the segment of the population that is less fit to survive. The differences which make them better fit for survival will be inherited by their offspring, and become an established characteristic of the species.
Since homosexual couples don’t have any biological children of their own, it is hard to imagine how a gene that discourages people from reproducing sexually could have evolved. Therefore, some scientists conclude that homosexuality must be a learned behavior influenced by cultural attitudes.
We are not taking a stand on whether homosexuality is genetic or cultural, good or bad, moral or immoral. Societal attitudes towards homosexuality are evolving—but that isn’t the kind of evolution Science Against Evolution addresses. We examine the various theories of biological evolution strictly from a scientific perspective, apart from religious considerations.
In this article, we examine the most recent attempt to explain homosexuality in the context of Darwinian evolution by a team of 11 evolutionary geneticists led by Brendan Zietsch at the University of Queensland in Brisbane, Australia.
As recently as two years ago, scientists were leaning toward the idea homosexuality was not genetic. According to the respected, peer-reviewed journal, Nature,
No ‘gay gene’: Massive study homes in on genetic basis of human sexuality
The largest study to date on the genetic basis of sexuality has revealed five spots on the human genome that are linked to same-sex sexual behaviour — but none of the markers are reliable enough to predict someone’s sexuality.
The findings, which are published on 29 August in Science and based on the genomes of nearly 500,000 people, shore up the results of earlier, smaller studies and confirm the suspicions of many scientists: while sexual preferences have a genetic component, no single gene has a large effect on sexual behaviours. 2
That strikes us as wishy-washy. They say there are gay genes—but they aren’t powerful enough to determine sexuality. But, as commonly happens with ideas which are political or philosophic (whether they pretend to be scientific or not) things change.
Just five weeks ago, Nature claimed,
Genetic patterns offer clues to evolution of homosexuality
To evolutionary biologists, the genetics of homosexuality seems like a paradox. In theory, humans and other animals who are exclusively attracted to others of the same sex should be unlikely to produce many biological children, so any genes that predispose people to homosexuality would rarely be passed on to future generations. Yet same-sex attraction is widespread in humans, and research suggests that it is partly genetic. 4
As we pointed out elsewhere in this month’s newsletter, computers can be programmed to suggest anything. If there is no way to confirm the simulation, the simulation is just a reflection of the opinion of the programmer.
In their opinion, same-sex behavior “is heritable.” In other words, they believe there are “gay genes,” which cause people to be homosexuals. This is controversial, and we admit we don’t know what the consensus in the scientific community is today; and it might not be the consensus by the time you read this article. We aren’t going to argue whether it is true or not. All that matters is that Zietsch believes they have identified what those gay genes are, and his team bases their analysis upon individuals who do (and don’t) have these gay genes.
Spoiler Alert! Their explanation is that some heterosexuals have these gay genes, too, and they are more sexually adventurous than average people, which results in more sexual experiences, which results in more offspring.
But let’s not get ahead of ourselves. Here’s what they say:
The fact that SSB [same-sex behavior] exists across human and animal populations is thus often discussed as a Darwinian paradox.
One possible explanation is that SSB has not been associated with reduced rates of reproduction. But human studies have found SSB to be associated with much lower reproductive rates in Western countries, even among heterosexually married individuals, and in Indonesia and a traditional Samoan community. In these studies, reproductive rates were reduced whether behaviour/attraction was oriented predominantly to the same or both sexes (especially see fig. 1b in ref. 19). Some scholars have concluded, based on these findings and anecdotal accounts in the anthropological literature, that same-sex attraction is cross-culturally associated with a large fitness cost. However, we note that, given that SSB has been subject to varying degrees of legal, medical and societal regulation, existing findings may not accurately reflect associations between reproductive rates and SSB in our evolutionary past. 5
You might be confused by their self-contradictory opening, “One possible explanation is that SSB has NOT been associated with reduced rates of reproduction. But human studies HAVE FOUND SSB to be associated with much lower reproductive rates. That confuses us, too.
Regardless of what they meant to say, the truth is that single-sex behavior results in a ZERO reproduction rate. Then they added, “even among heterosexually married individuals.” We think they mean that gay people married to a straight partner of the opposite sex do have children—but at a “much lower reproductive rate.” So, they seem to be including bisexuals with homosexuals. Forgive us if we don’t correctly understand their introduction—it’s confusing.
They recognize that homosexuals have been discriminated against in the past, and tended to remain “in the closet,” so it is difficult to make legitimate comparisons of current behavior with past behavior. We certainly won’t argue that point.
Their belief is that homosexuality is genetic, and involves certain combinations of genes, so we need to have a common background understanding of genes before we can explain their argument.
When you were in fifth grade, you were probably told about dominant and recessive genes. The example you probably heard involved brown eyes and blue eyes. You were told you got an eye gene from your mother, and an eye gene from your father. If both eye genes were brown, you would have brown eyes. If both eye genes were blue, you would have blue eyes. If you got a brown eye gene from one parent, and a blue eye gene from your other parent, you would have brown eyes because brown eye genes are dominant, and blue eye genes are recessive. Dominant genes are more “powerful” (for lack of a better word) than recessive genes, so they control the eye color. You were probably told about Gregor Mendel and his experiments with peas.
That’s an age-appropriate explanation for a fifth grader. When you got to ninth grade, you were probably given a more accurate explanation. Specifically, there isn’t a blue-eye gene and a brown-eye gene—there is an eye-color gene which has two alleles. “Alleles” is just another word for “variations.” There is a blue allele and a brown allele of the eye-color gene. There is just one eye-color gene—but it comes in two variations: blue and brown. That’s closer to the truth.
The truth is that eye color isn’t controlled by just one gene. There are several genes which affect the color of your eyes. All of the relevant genes have more than just two alleles, and some alleles are more common than others because some are more dominant than others. We are lucky that Gregor Mendel’s peas had few enough genes and few enough alleles that he was able to figure out the basics of genetic combination.
Many observable characteristics (probably most characteristics) are determined by multiple genes with multiple alleles, not just the presence or absence of a single gene.
Zietsch believes there are several genes associated with homosexuality, each of which has several alleles. If you want to know which genes, and which alleles, you can read his “massive study” to find out. All you really need to know is that his argument is based on the presence or absence of alleles of particular genes which he thinks are associated with homosexuality.
Zietsch’s argument is also based on a phenomenon Darwin called “Correlation of Growth.” Darwin correctly recognized that some genes have multiple functions which affect multiple physical characteristics. So, certain characteristics are correlated with others. If you have one characteristic, you have the other, too. For example, Darwin wrote,
… pigeons with feathered feet have skin between their outer toes; pigeons with short beaks have small feet, and those with long beaks large feet. Hence, if man goes on selecting, and thus augmenting, any peculiarity, he will almost certainly unconsciously modify other parts of the structure, owing to the mysterious laws of the correlation of growth. 6
You may not be familiar with the correlation of small feet and short beaks in pigeons, but you have probably heard other stories (which may or may not be true) about the correlation of foot size with other things. In addition to that titillating example, at the risk of being insensitive, you must know (even if you are unwilling to admit it) that you can usually tell that a person has Down’s syndrome simply by looking at his face. It may be politically incorrect to say so—but it is true. The genes which affect the brain also affect facial characteristics. There is a genetic correlation. The truth should not be denied simply because it makes some people uncomfortable; but these days, feelings seem to trump facts with certain people.
The article by Zietsch’s team is basically a correlation of growth argument. The alleles associated with homosexuality (they claim) have side effects (they claim) which lead to a more fertile sex life in heterosexuals who have those same genes (but do not have homosexual tendencies). It is an “Antagonistic Pleiotropy.”
Another possibility, which we investigate here, is that alleles associated with SSB confer an advantage to individuals who only engage in opposite-sex sexual behaviour (OSB individuals; see Box 1), thereby offsetting the fitness cost of the relevant alleles. In evolutionary simulations in the Supplementary Results, we show that such a situation can maintain substantial rates of SSB in the population (Fig. 1b), despite its fitness cost. The general phenomenon of alleles having multiple effects with opposing consequences with respect to fitness is called antagonistic pleiotropy and may be widespread. Using data from identical and non-identical twins, Zietsch [who refered to himself in the third person here] et al. provided indirect evidence consistent with the countervailing advantage of SSB genes, in that the genetic factors associated with SSB confered a mating advantage in OSB individuals (in terms of lifetime number of opposite-sex sexual partners; see Supplementary Discussion). A direct test of this hypothesis was not previously possible because the effects of specific genetic variants on SSB had not been characterized (early attempts to identify such effects used sample sizes and methodologies that are now regarded as underpowered for detecting effect sizes typical for complex traits, and their findings have not consistently replicated). 7
What scientists call, “antagonistic pleiotropy,” most other people call “trade-offs.” For example, if a company raises the price of their product, they will make more money on each one sold—but they will probably sell fewer of them, so the net effect of raising the price might increase or decrease profits. Changing prices has two consequences which oppositely affect profit. It is difficult to predict if the trade-off will increase or decrease profits because it depends upon the amount of the price change and the response in sales.
Buried in Zietsch’s report, filled with lots of statistical comparisons designed to determine the net effect of the antagonistic pleiotropy, is the conclusion,
These polygenic scores are genotype-based scores for each individual that estimate the extent to which their genotype contains variants associated with SSB. We showed that this polygenic score was positively correlated with lifetime number of opposite-sex sexual partners for OSB individuals, in both men and women. … Overall, these findings are largely consistent with the antagonistic pleiotropy hypothesis that alleles that are associated with SSB are also associated with a mating advantage in OSB individuals. 8
The study concludes that heterosexuals who have the gay genes tend to have more opposite-sex partners than average, which results in more offspring. That’s why natural selection has not eliminated homosexual behavior from humans and some other animal species.
But is the study correct? You can’t be sure because, despite its scientific appearance in a scientific journal, it isn’t scientific. Because people have been so badly educated about what science really is, many people don’t know the difference.
Let’s make this point perfectly clear: Genetic research is scientific. Scientists have intentionally destroyed certain genes in fruit flies and seen what happens as a result. This is how they know which genes are associated with wings, which genes are associated with eyes, and so on. When they find similar genes in other species, they generally have the same effect on those other species.
What we are saying is the genetic research is scientific because it is based on experimentation. It is repeatable. But conclusions based on genetics might not be scientific.
Paris really is a city in France. At the time when Victor Hugo lived there, there was a cathedral called Notre Dame, which really employed a bell ringer. Those facts are not sufficient to move Hugo’s novel, The Hunchback of Notre Dame, from the fiction to the non-fiction section of the library. A story based on scientific facts is still a story.
Pure water under one atmosphere of pressure boils at 100 degrees Celsius, whether you believe it or not. It doesn’t matter if you are a Republican or Democrat, Christian or atheist, water will boil at 100 degrees because that is a scientific fact. It has been proved countless times experimentally. The government can’t make it boil at 90 degrees to save the planet. Scientific truth is true whether it triggers a person of a particular sex or not.
Zietsch’s explanation of how homosexuality is compatible with Darwinian evolution is not scientific, despite the pages of statistics published in a scientific journal and the PhD degrees of Zietsh and his ten collaborating authors. Whether or not one believes his explanation depends largely upon whether one is prone to believe that homosexuality is the result of genetics or social experiences, and perhaps relevant religious beliefs as well. Zietsh’s paper is philosophy disguised as science. It is a Just So Story.
Like Zietsh’s paper, Darwinian evolution is philosophical, not scientific. That’s why, unlike the boiling point of water, it isn’t universally accepted by scientists.
Sadly, the general public has been indoctrinated to believe the theory of evolution is scientific, and the general public falsely believes all scientists believe in evolution. As a result, one of the most common reactions posted by critics on our Facebook is the claim that our name, Science Against Evolution, is nonsensical because (they think) the theory of evolution is the embodiment of science.
The fact remains that countless experiments over the past 70 years since Stanley Miller’s first failed attempt to prove abiogenesis (the origin of life from non-life) have all failed. Sooner or later, one must admit that Louis Pasteur was right because his experiment has been repeated countless times, and it is the basis for sterilization in the food and medical industries. Every living thing today came from a previous living thing, plant or animal, microscopic or visible with the naked eye. Abiogenesis as the foundation for evolution as an explanation for the origin and diversity of life is dead on arrival. It’s a non-starter.
Countless breeding experiments (including the Kentucky Derby) have proved that breeding can enhance characteristics from color to drought resistance to strength and speed—but there is always a limit. Small changes (microevolution) do not accumulate enough to create entirely new forms of life with novel characteristics (macroevolution) no matter how long you wait.
Abiogenesis and Darwinian evolution both violate known scientifically established facts. Science is against evolution.
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J. Maynard Smith, Nature, March 20, 1975, “Evolution of Sex”, https://www.nature.com/articles/254221a0
2 Jonathan Lambert, Nature, 29 August 2019, “No ‘gay gene’: Massive study homes in on genetic basis of human sexuality”, https://www.nature.com/articles/d41586-019-02585-6
3 Sara Reardon, Nature, 23 August 2021, “Genetic patterns offer clues to evolution of homosexuality”, https://www.nature.com/articles/d41586-021-02312-0
4 Zietsch, B.P., Sidari, M.J., Abdellaoui, A. et al., Nature Human Behaviour, 23 August 2021, “Genomic evidence consistent with antagonistic pleiotropy may help explain the evolutionary maintenance of same-sex sexual behaviour in humans”, https://doi.org/10.1038/s41562-021-01168-8
6 Darwin, 1859, On the Origin of Species by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life, Chapter 1.
7 Zietsch, B.P., Sidari, M.J., Abdellaoui, A. et al., Nature Human Behaviour, 23 August 2021, “Genomic evidence consistent with antagonistic pleiotropy may help explain the evolutionary maintenance of same-sex sexual behaviour in humans”, https://doi.org/10.1038/s41562-021-01168-8