Nature or Nurture? A debate revisited

Maloi takes a thorough look at the major historical theories of homosexuality and the recent trends within the world’s scientific community on this ancient debate.

Homosexuality has always been a part of human society, only that is has not been talked about and swept under the carpet since centuries. With the advancements in the fields of psychology, genetics and the allied sociobiologists, human rights activists have become more intrigued about what goes behind homosexuality and so it has become one of the most debated issues in these times. Many scientists have worked for centuries trying to understand the genesis of homosexual behaviour. A lot has been postulated but hereunder is in a nutshell all that has been hypothesised, studied and proven.

Psychoanalytical theories

This theory states that most families of homosexuals are characterized by an overprotective mother and an absent father. Homosexuality may be an expression of nonsexual problems, such as fear of adult responsibility, or may be triggered by various experiences, such as having sexual relationships with members of one’s own sex at an early age that prove to be very satisfying. Arguments regarding the roots of lesbianism include disappointing heterosexual love experience, a father who displays distaste for men who express interest in his daughter, and memories of abusive relationships with men. It is believed that all humans were born bisexual in nature, and from this state, as a result of restriction in one direction or the other, both heterosexuality and homosexuality developed . One or more of the following factors is unusual in some respect in the childhood of homosexuals: parental hopes before birth for a child of the other sex; difficulties at birth; slight anatomical differences between identical twins leading to a special attachment of one child or the other to their mother; strength of the relationship between father and child; competition for the affections of the mother; the individual’s birth order, parental age at birth, and family size. Homosexuality has also been linked to childhood opposite sex-dimorphic behaviour, such as effeminacy in boys. However, such behaviour is not observed in all pre-homosexual children while it is also seen in some pre-heterosexual children. It is quite possible that, rather than being causative of adult sexual orientation, such behaviour is the manifestation of an innate predisposition towards homosexuality. Researchers have provided evidence that gay men report having had less loving and more rejecting fathers and closer relationships with their mothers, than non-gay men. Key factors in the development of homosexuals were “paternal attachment, introversion, and neurotic characteristics.”

Genetic hypothesis

Xq28 is the locus on chromosome X that carries the homosexuality trait
Homosexuality arises through the interaction of particular genetic propensities with specific rearing environments. The genetic theories of sexual orientation attempt to show that it is possible that homosexuality can be sustained in a population through purely genetically controlled processes which have been subject to the pressures of natural selection.

The two most popular hypotheses in this field are those of balanced superior heterozygote fitness and of kin selection for altruistic behaviour.

Briefly, the former hypothesis supposes that phenotypic homosexuality is the result of homozygosity for recessive ‘homosexual’ genes. If a heterozygote, possessing one ‘homosexual’ genetic allele and one ‘heterosexual’ allele, is phenotypically heterosexual, and more reproductive than an individual who is homozygotic for the ‘homosexual’ alleles, then the heterozygotic combination will be preferentially selected in future generations. In this way, the ‘homosexual’ genes are preserved. This explanation may seem implausible; for one thing, it hardly seems likely that only a single, major gene is involved in determining sexual preference. However, various genetic concepts (incomplete penetrance, epistasis, etc.) may be utilized to expand the hypothesis

The key to the kin selection hypothesis is that it does not matter how one’s genes are passed to the next generation, as long as they are. Siblings share, on average, 50% of their genes. Therefore, if an individual shows altruistic behaviour towards its siblings which results in an increased likelihood of the siblings leaving or raising offspring, then that individual is, in effect, favouring its own success. Although it is hard to see how such a process could operate in modern society, sociobiology concerns itself with how behavioural traits have evolved and been selected from primitive societies to the present day. It has been suggested that, in primitive societies, homosexuals may have formed a ‘sterile caste’ which could devote itself to helping mothers to rear their young.

Neurohormonal hypothesis

The early fixation hypothesis includes research into prenatal development and the environmental factors that control masculinization of the brain. Studies have concluded that there is empirical evidence to support this hypothesis, including the observed differences in brain structure and cognitive processing between homosexual and heterosexual men. One explanation for these differences is the idea that differential exposure to hormone levels in the womb during fetal development may block or exaggerate masculinization of the brain in homosexual men. It is proposed that sexual orientation is primarily determined by the degree to which the nervous system is exposed to testosterone, estradiol, and to certain other sex hormones while neuro-organization is taking place, predominantly between the middle of the second and the end of the fifth month of gestation. Complex combinations of genetic, hormonal, neurological, and environmental factors operating prior to birth largely determine what an individual’s (adult) sexual orientation will be.

The concentrations of these chemicals are thought to be influenced by fetal and maternal immune systems, maternal consumption of certain drugs, maternal stress, and direct injection.

Recent developments

While the theories of psychoanalysis, as espoused by Freud are fast losing credibility along with his other theories, alternative ones that suggest a biological origin of sexual orientation is now gaining a consensus among the scientific community, exactly what gay activists have been rooting for as they believe that society would be more pre-disposed towards accepting gays if it’s proved that they are born that way.

A Swedish study, published in the Proceedings of the National Academy of Sciences journal suggests that the brains of gay men and women look like those found in heterosexual people of the opposite sex.

According to the report, in heterosexual men and gay women, there were more nerve “connections” in the right side of the amygdala, compared with the left. The reverse, with more neural connections in the left amygdala, was the case in homosexual men and heterosexual women. The research team said that these differences could not be mainly explained by “learned” effects, but needed another mechanism to set them, either before or after birth.

Born gay?

On this, the BBC reported-

‘Dr Qazi Rahman, a lecturer in cognitive biology at Queen Mary, University of London, said that he believed that these brain differences were laid down early in foetal development.

“As far as I’m concerned there is no argument any more – if you are gay, you are born gay,” he said. “The amygdala, he said, was important because of its role in “orientating”, or directing, the rest of the brain in response to an emotional stimulus – be it during the “fight or flight” response, or the presence of a potential mate.

“In other words, the brain network which determines what sexual orientation actually ‘orients’ towards is similar between gay men and straight women, and between gay women and straight men.

“This makes sense given that gay men have a sexual preference which is like that of women in general, that is, preferring men, and vice versa for lesbian women.”’

That may be true, but it’s still some time before we gear the final word on this debate.