Unchosen:
The Science Behind Same-Sex Attraction

When Did I Decide to Be Straight?

I didn’t.

I’ve loved my female friends deeply, but never romantically. I never chose it. I never questioned it. Being straight isn’t a decision I made. It’s simply who I am. No matter how much I care, I wouldn’t be able to force that kind of attraction.

That’s how it is for my gay friends. Whether or not they act on it, their romantic and physical feelings show up only for people of the same sex.

Some people do experience attraction towards people of both genders. Many don’t realize that not everyone shares that kind of flexibility. Without that understanding, some can be quick to judge those who don’t have the same options.

Behind the scenes, science has discovered a complex dance that determines who we are attracted to, a combination of senses, hormones, brain chemistry, smells, and even immune responses, all firing in milliseconds. What feels like magic is actually biology in motion. Chemical reactions we can’t control. We can control our actions, but we can’t control if we find ourselves attracted to someone. We don’t choose who we’re drawn to. It just happens.

Let’s look at what science has discovered. But first, a walk down history lane.

A History of Scientific Harm and Healing

Centuries of Silence

Hippocrates (c. 460–370 BCE), the “Father of Medicine,” never mentioned same-sex attraction in his writings, despite its common presence in Greek society. Neither did Galen (200 BCE), one of the most influential medical researchers of antiquity. Galen did, however, reinforce the cultural belief that male bodies were superior and female bodies were deviations. In ancient sexual norms, encounters were framed in terms of dominance and submission, not gender. It was socially acceptable for a man to take the dominant role, whether the passive partner was a woman, a slave, or a young male.

Acknowledged and Named

Not until the 1800s did scientists begin studying same-sex attraction. Karl Heinrich Ulrichs coined the term “urning” for men who loved men, declaring it an inborn trait. Karl-Maria Kertbeny soon introduced the word “homosexuality,” shifting the discussion from behaviors to who they are. In 1870, psychiatrist Karl Friedrich Otto Westphal described homosexuality as an inborn trait. Sigmund Freud saw it as a developmental variation, but later psychoanalysts like Sandor Rado and Edmund Bergler blamed it on childhood trauma and maternal issues.

Pathologized as Illness

In the late 1800s and early 1900s, while doctors were saying that homosexuality was an inborn trait, psychiatrists started classifying it as a mental illness. Physicians, like Havelock Ellis and Magnus Hirschfeld, argued it was natural, not sinful. But psychiatrists, like Bénédict Morel and Richard von Krafft-Ebing, framed it as a neuro-psychopathic disease. Believing it could spread like a disease and “weaken” German manhood, society, and military readiness, the Nazis criminalized homosexuality, sentencing over 50,000 men to prison. Many were tortured, castrated, or killed. In the U.S., Cold War fears linked homosexuality to instability and national threat.

“Curing” the Gay Out

During the 1930s, UK psychiatrist Louis Max introduced chemical and shock therapies to try to change homosexuals. Some of his patients were injected with emetics, then confined with pictures of unclothed men and their own uncleaned vomit, to associate same-sex attraction with disgust. Others were given shock therapy, involved attaching electrodes and delivering pain whenever a subject saw images of men and showed arousal. Some floors were wired to shock their feet.

Fighting Back in the ’60s and ’70s

In the ’60s and ’70s, gay people were often arrested, harassed, or beaten by police simply for gathering in public, appearing “effeminate” or sitting “too close” to someone of the same sex. But people started speaking up. Psychiatrist Thomas Szasz argued that psychiatry was being used to scapegoat Jews, gypsies, and homosexuals. Judd Marmor led the effort to remove homosexuality from the DSM (Diagnostic and Statistical Manual of Mental Disorders), stating it was not a mental illness. The Mattachine Society, one of the first gay rights organizations in the U.S., organized discussions, protests, and legal advocacy. Dr. John Fryer risked his career to speak (in disguise) at the American Psychiatric Association. The 1969 Stonewall uprising marked a turning point, igniting national activism.

Science Begins to Understand the “Whys”

Starting in the 1980s and accelerating into the 2000s, researchers began to uncover biological differences between gay and straight people.

Brain Structure. Research found that the brains of gay males resembled that of straight females, and lesbian female brains resembled straight male brains. Researchers found differences in all four areas of the brain:

• Amygdala (involved in emotion, arousal, and sexual behavior)
• Hypothalamus (regulates hormones, sexual behavior, and attraction)
• Corpus Callosum (connects the left and right hemispheres of the brain)
• Cerebral Cortex (brain symmetry)

Pheromone Response. When exposed to male pheromones, gay men exhibit similar patterns of brain activity as straight women, unlike straight men.

Finger Length Ratios. Not al, but lesbian women tend to have shorter index finger compared to ring finger, suggesting higher prenatal testosterone exposure.

Startle Reflex. Lesbian women show a startle reflex pattern more like straight men, indicating biological variations in sensory processing.

Chromosomes. Genetic studies have identified regions on the X chromosome linked to same-sex attraction, particularly in men.

Functional Brain Connectivity. Gay adults display distinct neural connectivity patterns in areas related to self-perception, reward, and social behavior.

Cochlear (Ear) Responses. Gay women have weaker inner-ear sound emissions than straight women, mirroring typical male patterns and suggesting a biological difference formed early in development.

Some people show many of these differences, others only a few. Some traits are more pronounced, others subtler. Masculinity and femininity exists on a spectrum. Some women are more masculine and some are more feminine. And the same goes for men. These traits can show up in behavior, voice, style, posture, or even biological markers. All traits that we have no control over.

Researchers include: Simon LeVay (neuroscientist), Dick Swaab (neuroscientist), Michel Hofman (neuroanatomist), Christoph Abé (neuroscientist), Ivanka Savic (neuroscientist), Per Lindström (neuroscientist), Håkan Lindström (researcher), Qazi Rahman (neuroscientist and psychologist), Sandra Witelson (neuroscientist), Grimbos et al. (psychologist), William Rice (geneticist), Urban Friberg (biologist), Dean Hamer (geneticist), Andrea Ganna (geneticist), Brendan Zietsch (geneticist), Zhang et al. (neuroimaging research group), Dennis McFadden (auditory neuroscientist).

What caused these differences?

Genes & Epigenetics

Brendan Zietsch led the largest-ever study on genetic contributions to same-sex behavior. Genetics links were detected, but no “gay gene” was found. Tuck Ngun and Eric Vilain led separate teams that finally found the answer. They identified epigenetic markers, chemical tags that “travle” on the genes and influence how DNA is expressed, that specifically associated with male homosexuality.

Prenatal Hormones

Studies found that hormone exposure in the womb, especially during key weeks of brain development, affects sexual differentiation. High testosterone in females is linked to lesbian orientation. Lower or altered testosterone in males contributed to gay orientation.

Maternal Immune Hypothesis

Studies found that each male pregnancy increased a maternal immune response to a male-specific protein (NLGN4Y), potentially altering brain development in later sons. This “fraternal birth order effect” increases likelihood of being gay by 3–4% per older brother (Bogaert et al., 2018).

A Medical Consensus: Being Gay Is Not a Choice

These discoveries have led nearly every major medical and psychological association to issue formal statements or policy positions affirming that homosexuality is not a mental illness and that attempts to change sexual orientation are ineffective and harmful. These organizations include:

• American Psychological Association
• American Medical Association
• Academy of Pediatrics National
• Association of Social Workers
• National Human Genome Research Institute
• Broad Institute of MIT and Harvard
• American Psychiatric Association
• Centers for Disease Control and Prevention (CDC)
• American Counseling Association
• American School Counselor Association
• American Academy of Family Physicians
• National Association of School Psychologists
• American College of Obstetricians and Gynecologists
• American Academy of Child and Adolescent Psychiatry
• American Public Health Association
• European Bioinformatics Institute
• World Health Organization (WHO)
• Royal College of Psychiatrists (UK)
• Australian Psychological Society
• Canadian Psychological Association
• Psychological Society of Ireland
• New Zealand Psychological Society
• British Psychological Society
• Pan American Health Organization (PAHO)
• European Psychiatric Association
• Karolinska Institutet (Sweden)
• and so many more

Can Gay People Turn Straight?

Can Gay People Turn Straight?

The now-defunct ministry Exodus International once claimed they could change people’s orientation. After 37 years and over 600,000 participants, they shut down and issued a public apology. Former president Alan Chambers admitted, “No therapy, no ministry, no prayer meeting, no nothing, can change your sexual orientation.”

What about those that say they did change?

Many who claim to have “left homosexuality” were actually bisexual, and had an easy time just switching to just focusing on one gender. Others left a life of addiction, not orientation. Some decided to stay celibate and called it a change. Some continue to experience same-sex attraction but redefine it as temptation or sin.

Stories that mislead

• John Paulk, after 15 years of being an ex-gay voice for Focus on the Family, and claiming to have changed, he later renounced his claims and apologized.
• Rosaria Butterfield, often featured by Focus on the Family, likely represents a bisexual shift, yet publicly now promotes harmful anti-gay rhetoric.
• Christopher Yuan, a self-described “former homosexual” who tells his story of a “gay past” of drug use, prostitution, and addiction, he has openly acknowledged that he is not heterosexual yet. An article published in 2022 quotes Yuan stating that same-sex desires are sinful even when not acted upon. In The Holy Sexuality Project, a project he created for young teens, he tells them that if they marry someone of the opposite sex, “God may later give you the feelings you need for just that one person,” a message that has had disastrous repercussions in people’s lives.

Understanding Leads To Compassion

Science has found that we don’t choose that orientation. We discover it. The overwhelming conclusion across decades of research is that sexual orientation is not a choice, cannot be changed, and that attempts to do so can cause lasting psychological harm.

Science does not show us whether something is a sin or not, but it does help understand what people are experiencing. It leads us to understanding. That understanding, in turn, should stir compassion in us, enough to rethink how we treat others from the judgment seat. That compassion should move us to reexamine whether our condemnation is truly faithful to Scripture, and whether our interpretations reflect the heart of Christ.

If our response does not produce the fruit of the Spirit, then we might not be standing for truth, we are standing in the way of it. If our convictions drive people to despair, maybe they came more from fear than from Jesus.

From Researching to Listening

We can study science. We can debate theology. But at some point, we have to stop talking about them and start listening to them, to their stories. If you’ve never heard what it’s like to grow up gay in a church pew, to pray for years that God would make you straight, or to finally come out and lose everything, I encourage you listen to their stories.

• Through My Eyes (47 min), interviews with Christian gay young people
• Tim Ouyang (2024, 51 minutes), Christian gay musician, tells a powerful story of coming out
• Justin Lee (2020, 15 minutes), Christian gay author and speaker, tells his story
• Vicky Beeching (2015, 6 minutes), Christian gay music artist, tells her story of coming out.
• Matthew Vines (2019, 52 minutes) and his dad tell the story of him coming out and studying to see what the Bible has to say about it.
• Sally Gary (2023, 52 minutes) tells her story of how she knew she was gay from the time she was little, but wanted to follow Jesus, so decided to just remain celibate.
• Gabriel Eurell (2024, 51 minutes) tells his story (starting at minute 16) of realizing at the age of 12 that he was gay.
• For The Bible Tells Me So (2007, 1 hr 35 min, Apple TV) tells the story of five very normal, Christian, American families, and how they handle the realization of having a gay child or family member.

Stories don’t prove truth, but they invite us to confirm our truth. Jesus said, “You will know them by their fruit” (Matthew 7:16). Not by their theology. Not by their ability to fit a mold. By their fruit.

Our Response

Attraction isn’t chosen, but our response to others is.

The science is clear: sexual and romantic orientation is a natural variation of human experience.

The gospel is clear too: our calling is to reflect the love of Christ in how we treat others, a call to justice, compassion, and helping the oppressed.

May we discover truth before judging, both scientifically and biblically.

If our response doesn’t lead to mercy, humility, and compassion, then it’s time to ask whether we’ve misunderstood the heart of the one we claim to follow.

Is being gay just a sexual temptation? (Justin Lee 13 min)
Is sexual orientation genetic or a choice? (Justin Lee 3 min)
Untangling the Mess (Kathy Baldock 1.28 hrs)
Pray Away (Documentary 1.41 hrs)