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Ethon Lowe: Homosexuality: nature or nurture?

Published:Tuesday | January 19, 2016 | 1:00 AM
Ethon Lowe

It may be expecting too much for guidance counsellors (presumably predominantly Christians) to be stalwarts of objectivity, impartiality and compassion when offering guidance to students who have problems with their sexual orientation.

We hope that these students will be reassured, as the Rev Peter Espeut was quick to point out in his column ('Made, not born', Gleaner, January 16, 2016) that at this early age, bonding with your own sex is common, if not normal, and is part of growing up.

Can we be sure that these students won't be subjected to a barrage of fire and brimstone, reproached and ostracised with the all-too-frequent mantra: "Homosexuality is a sin. Homosexuality is not natural!"

Can we afford another generation of children indoctrinated in the fundamental beliefs of the Christian faith? If homosexual behaviour in 1,200 species of our animal precursors, including our closest animal relative, the chimpanzee, is not natural, what is? This is not only further proof that homosexuality is at least partly genetic, but also belies the notion that gay sex is a human innovation. What is certainly not natural is the Virgin Birth and, yep, a talking snake.

Studies in identical twins (monozygotic - derived from a single egg) with the same genes have shown that homosexuality is significantly more common than in non-identical twins (dizygotic - derived from two separate eggs). There is a 20 per cent concordance among the identical twins (University of California study, October 15, 2015). It is also more common in families.

 

GENES AND HORMONES

The extent of the inheritance is, however, lower than expected. Although there is strong evidence for a biological basis for homosexuality, there seem to be other contributory factors such as epigenetics, which is the effect of hormones, drugs, chemicals and the environment on genes either in the uterus or after birth. Hormonal studies, for example, reveal that the brains of gay men may not receive the full amount of testosterone at the right time during foetal development and are insufficiently masculinised.

A study of the brain (Journal of Science, 1991) showed that the hypothalamus, which controls the release of sex hormones from the pituitary, is much smaller in size in gay men than in straight men. Other changes were seen in other parts of the brain.

The paradox is why, if gays don't frequently reproduce, is gayness still being passed on? Why has it not been eradicated by natural selection? One explanation (not very plausible, in my opinion) is that the group of genes that codes for homosexual orientation may, at other times, have a strong reproductive benefit. It has been demonstrated that female relatives of homosexual men (who carry their genes) have more children on average than women that do not have. Another puzzle is, if gays were born gay or straight, why do some switch in midlife from homo to hetero, and vice versa?

Some homosexuals openly admit that their lifestyle is a choice. No doubt the same is true for heterosexuals. How do you explain bisexual people? While genes and hormones may predispose a person to a particular sexual orientation, other factors such as social expectations (what is acceptable in one's society, and the freedom to out oneself), cultural values and peer pressure may help to push many towards a particular sexual preference.

There is no evidence of a gay gene, but some genes may more likely lead to homosexuality (like probably genes for religiosity and artistic talents, etc) What is true is that some people are exposed to a combination of genetic and environmental circumstances that impel them strongly towards a homosexual life style. What is more important is that there should be no inherent conflict (forget Leviticus 20.13) between homosexuality among consenting adults and the welfare of other people.

- Ethon Lowe is a medical doctor. Email feedback to columns@gleanerjm.com and ethonlowe@gmail.com.