THE BIOLOGY OF HOMOSEXUALITY
Dr. Lester CN Simon
With the reaction to homosexuality in the West Indies ranging from militant objection to public ridicule, ostracism and benign intolerance, I have often questioned the biological advantage of homosexuality to the human race. Clearly, it is not genetically reproducible in that homosexuals, by definition, do not naturally have sexual intercourse with members of the opposite sex. Science is beginning to shed some light on the advantage homosexuality might confer on the rest of us.
An article called, The Evolution of Homosexuality, in The Economist, on 23 October, suggests that the genes that contribute to making some people homosexual also make their brothers and sisters highly sexually productive. This enhanced sexually reproductive effect on the non-homosexual siblings is regarded as an advantage to the human race.
The first hurdle a skeptical reader has to overcome is the scientific fact that homosexual behaviour is documented in many species. These include monkeys, gorillas, chimpanzees, geese, hyenas, whales, worms, dolphins, flamingos, and many others. The simple response to this fact might be to label human homosexuals as animals and insects. But what about the body of scientific evidence that suggests that homosexual behaviour, indeed any type of sexual behaviour, is partly genetic? These studies look at the sexual proclivities of twins, especially identical twins.
There are two different types of twins. One type of twins is called non-identical. These twins occur when two eggs from the mother are independently fertilized by two different sperms from the father. These twins can be of the same or different gender: two boys or two girls or a boy and a girl. The other type of twin is called identical. Identical twins are produced when a single egg is fertilized by a single sperm and the fertilized egg divides into two separate embryos of the same gender: two boys or two girls but not a boy and a girl.
Unlike non-identical twins, identical twins have identical genes (DNA). Notwithstanding their identical genetic status, the traits and appearance of identical twins can vary depending on the environment they are exposed to, both inside the womb and throughout their lives. This variability, even in the presence of identical genes, underscores the basic fact that our appearances and behaviors, including our sexual behaviors, are influenced by genes as well as by our environment. The perennial argument revolves around the extent of the contribution of the genes versus the effect of the environment.
Studies of identical twins (male twins and female twins) show that if one of the twins is homosexual, there is a 50% chance of the identical twin brother or identical twin sister being homosexual. This 50% chance is much higher than what obtains for non-identical twins or for non-twin brothers and sisters. The 50% concordance for homosexuality amongst identical twins of either sex-pair (two males or two females) leads to the consideration of the sexual orientation of the identical twin brother or twin sister when such a brother or sister is not homosexual despite having a homosexual identical twin. After all, they do have identical genes.
Genes explain about 27% of an individual’s gender identity. Environment explains the rest. So what exactly are the genes associated with homosexuality, responsible for in a non-homosexual person? The article in The Economist reports the work by Brendal Zietsch et al of the Queensland Institute of Medical Research in Brisbane, Australia. The original work was published in this month’s edition of the journal, Evolution and Human Behavior. The scientists analyzed anonymously completed questionnaires from 4904 twin samples regarding sexual behavior and attitudes.
The arguments of the scientists include the suggestion that if a non-homosexual man has a very slightly feminine personality, it confers an advantage on him when viewed by a non-homosexual female. Despite the female’s desire for a traditional macho man, she is also attracted to the man’s so-called feminine traits such as tenderness, consideration and kindness. Indeed, these kinder, gentler males, despite the boastfulness of the macho male, are said to have more female sexual partners than the typical macho man. In fact, it is said that the judicious display and tweaking of these so-called feminine traits of tenderness, consideration and kindness is a trick some men use (I am told) to appeal to females. Up comes a hailstorm counterargument regarding the definition of maleness and femaleness.
On the other hand, slightly masculinised females who are not lesbians, are said to have more non-homosexual male sexual partners than the typically, highly feminized, non-lesbian woman. This is thought to reflect her increased competitiveness over other women (and arguably some men). Many honest, hardworking, assertive, non-homosexual women are often, erroneously and deliberately labeled as lesbians by both men and women as she supersedes the latter two at work and at play.
It appears that if you combine sexual proclivities and the number of sexual partners, disparate collections of data suggest that the ranking order from top to bottom (no pun intended) might be as follows: dominant male homosexual, non-homosexual twin brother of male homosexual, non-homosexual male, dominant female homosexual, non-homosexual twin sister of female homosexual, non-homosexual female. It is not clear where the non-dominant male homosexual and the non-dominant female homosexual fall. Indeed the ranking order, especially that of dominant lesbian and of non-homosexual twin sister of female homosexual might need some alterations. Ranking may be influenced by male boasting or female bashfulness regardless of the bending of gender.
The study concludes that as long as the combination of genes associated with homosexuality do not push individuals all the way to homosexuality, these very genes that are partly responsible for homosexuality also partly confer advantages to non-homosexuals. These genes arguably make non-homosexuals males and non-homosexual females who carry these homosexual-associated genes, more sexually productive compared to non-homosexual males and non-homosexual females who do not carry these genes. Regarding the advantage to the human race, the self-defining, non-reproducible genetics inherent in homosexuality is arguably offset by the excessive sexual reproductive capacity or fecundity in others.
Small wonder some homosexuals reportedly do not see what all the fuss over their sexual orientation is all about. We say we do not understand them and they say they do not understand us. They fail to understand us because some non-homosexuals who attack them (both within and without the dancehall lyrics), and who ridicule and ostracize them, will otherwise skillfully maneuver small aliquots of some of the very traits homosexuals have, to a personal advantage and to the advantage of the human species.
It might be argued that the homosexual male and female involuntarily or voluntarily simply push the envelope containing sexually related genes and environmental sexual determinants farther, to the extreme even; and, some would say, too far.