1. Born This Way – Reflections (Science)

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.


About coagec

I am a single Christian man with same sex sexual attractions who believes in traditional sexual ethics. My relationship with Jesus is the most important thing in my life. My church home is with the Presbyterian Church in America (PCA). I love my work as a physician, as I get to participate in God's work of healing.
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6 Responses to 1. Born This Way – Reflections (Science)

  1. DrewTwoFish says:

    I think the bottom line is that we just.don’t. know. We don’t know how sexual attraction develops, be it straight or other. I think it’s overreaching to say that our sexuality defines us but it certainly is an integral part of who we are be it “disordered” or not. And our orientations are most definitely not chosen.


    • coagec says:

      Thanks DrewTwoFish for your comment. I think the evidence indicates a mix of genetic and environmental causal factors, but the exact mechanism certainly needs more work to flesh out. I agree with you that sexuality is an integral part of who we are, though for a Christian, I believe sexuality should not define us though it often does for both heterosexuals and homosexuals.


  2. I’ve had this page on file for a while. Thoughts?


    • coagec says:

      The article in the link is suspect for several scientic reasons. First, the largest and most recent twin study from 2010 that involved all identical twins in Sweden showed that among males, genetics explained 34-39% of sexual orientation, individual specific environmental factors (including prenatal environment) explained 61-66%, while shared environmental factors (including family environment) explained 0%. Corresponding numbers for females were 18%, 64%, and 16%, respectively. Selection bias is a major issue in these studies, but by studying all twins in a country, this study has the most valid results with regard to this bias. This study clearly shows that genetics and prenatal environment play important if not determinative roles in formation of sexual orientation. Furthermore, the linked article makes the fundamental error of taking an all or nothing approach with regard the roles of nature vs nurture in heritability of personality traits. My discussion above and the Swedish study I believe amply demonstrate the flaw in this all or nothing approach. Just to reiterate, ALL personality traits are a mix of genes and the environment.


      • DrewTwoFish says:

        This is what I don’t get Coagec:

        Your response to the Holland Davis article, among other things, tells me that you’re obviously an intelligent man capable of processing information through a rigorous scientific filter. And yet you take on faith (I’m guessing) a fascinating mess of contradictions, i.e. the Bible in its entirety. You condemn yourself to a life of celibacy because “God’s word” tells you that even a loving, committed, and monogamous same sex relationship that brings benefits to the participants and no harm to anyone else is somehow wrong.

        I suppose I should be more understanding because, to some extent, I was in the same position. I do get that Jesus is someone worth emulating and that there is some wisdom in the Bible. I can appreciate the desire to find meaning beyond ourselves. But I really don’t understand why we must regard every syllable as God breathed especially when doing so seems to do real harm (war, misogyny, oppression and so on).


      • coagec says:

        Thanks for your comment Drew. Your reaction is actually not uncommon. Indeed, I am both a man of science and a man of faith. For me, they are entirely complementary, as both are avenues for understanding truth about myself and the world I live in. I think I actually approach faith matters with scientific rigor, though of course there are some differences between the two domains. I do indeed accept the entire bible as authoritative and infallible word of God, but I have reasons for this belief that for me satisfy a personal scientific standard. Some of these reasons were discussed in my Born Again series. I will discuss the matter in detail in the upcoming Homosexuality series, but I find the celibate life in Christ to be far more rich than the life I would have if I were to pursue a homosexual relationship. So for me, my choice both meets a theological perspective and provides a more fulfilling life. On the point you made about how reading every word of the bible as God inspired leads to harmful effects, while there is no doubt that bad things have occurred in history by the hands of those who cited scripture, I would simply note at this time that these were misreadings of scripture and that correct reading and application would lead to the kind of holy, just, and loving world described in the bible.


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