Whence could such a creature come but from thee, O Lord? Is any man skillful enough to have fashioned himself? Or is there any other source from which being and life could flow into us, save this, that thou, O Lord, hast made us–thou with whom being and life are one, since thou thyself art supreme being and supreme life both together.
– The Confessions of Saint Augustine
No matter gay, straight, or bi, lesbian, transgendered life, I’m on the right track baby, I was born to survive.
– Lady Gaga
The issue of the origins of homosexuality is controversial, to put it mildly. In my last post, I shared how same sex sexual attractions first manifested in my own life. In this companion post, I will discuss the origins of homosexuality from a scientific perspective. This isn’t meant to be a comprehensive review that I might write for a medical journal but will instead be conversational and comprehensible (hopefully!) for those not trained in this area.
Scientific and pseudo-scientific theories have abounded over the years. Prior to homosexuality being removed as a psychiatric disorder by the American Psychiatric Association in 1973, homosexuality was most commonly viewed as resulting from developmental factors in childhood, most significantly deficiencies in the child’s relationship with his parents. With the rise of the gay rights movement and reexamination of the available data, biological factors have increasingly been viewed as playing a significant, perhaps even dominant, role. Politics has unfortunately made an objective and scientifically rigorous examination of this issue difficult. Gay rights activists often promote the “nature” causes while ridiculing “nurture” causes as homophobic because being “born this way” is an important part of the gay narrative and moral justification. Traditionalists often promote the “nurture” causes while minimizing “nature” causes because upholding biological hetero-norm and moral disapprobation are paramount. The truth, as often is the case in controversial matters, is somewhere in the middle, namely both biological and developmental factors likely contribute to the emergence of same sex sexual attractions.
This should not be a controversial or difficult proposition for anyone familiar with the development of human traits. DNA encodes various genes that serve as the blueprint for all human features. There is nothing in the human being, whether considered physiological or psychological, that does not have some genetic causality. However, this does not mean than our DNA fully accounts for any of our features. Just as a house must be built from a blueprint, the human form only results as the encoded features in DNA are given shape through the expression of these genes. The expression of genes in turn is heavily influenced by an organism’s environment. This is particularly important in utero, while the fetus is developing, but the expression of genes occurs throughout life and continues to be influenced by the environment. To complicate matters further, there is something called epigenetics, which is how biochemical factors within cells determine which genes are expressed. Recent research shows that these epigenetic features are impacted by the environment and can be passed on to the next generation, meaning that a parent’s experiences can directly influence which genes are expressed in the child.
What all this means for the origin of homosexuality is that homosexuality certainly results from a mix of genetic and environmental factors. One often cited statistic is that among identical twins who share exactly the same DNA, the sibling of a homosexual person has about 30% chance of being homosexual, which is a higher figure than for fraternal twins who do not have identical DNA, which in turn is higher than for the general population. The least biased interpretation of this data is that the higher rate for the identical twin results from a genetic predisposition (i.e., blueprint) for homosexuality, but this is merely a predisposition and not entirely determinative since a majority of identical twins of homosexuals ends up being heterosexual. What likely accounts for the different outcomes is the environment, both in utero and early childhood development. Some environmental theories have been proposed, including maternal hormonal levels during pregnancy and child attachment during early years, but the data is not very strong and additional research is needed.
Hence, it would be more correct to say that humans are born with a genetic predisposition towards opposite or same sex sexual attraction, but the orientation that ultimately results also depends on environmental factors. The precise mix of nature vs nurture likely differs for each individual, so that someone with a strong genetic predisposition for homosexuality will likely have same sex sexual attraction regardless of the environment, whereas another person with a weak genetic predisposition will only develop same sex sexual attraction with strong environmental factors. Despite the uncertainties, it is clear that much of the determinants of same sex sexual attraction are beyond the control of an individual, making claims of people “choosing” to have same sex attraction spurious. In the end, though, the moral import of same sex sexual attraction is less determined by how it comes about scientifically and more by the theological understanding one has regarding it. That is the topic I will address in my next post.