What the Causes of "Homosexuality" Taught me about Transgender

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Stepping into the transgender debate

In researching my website, the Affirming Evangelical, I explored the causes of homosexuality. But in doing so I found myself drawn into a deeper understanding of gender and biological sex and towards the more complex, controversial debate of transgender identities.

With our sexuality, I found that, contrary to my original traditionalist views, science now clearly points towards biology as nearly always being the cause of our sexuality, mostly before we're even born. Studies also overwhelmingly indicate that our social environment plays no part in male same-sex attraction and only a rare, weak part for females. Science has now found our sexuality is nearly always caused by a complex interplay of biological factors beyond our control - neurological, genetic, epigenetic, hormonal, chromosomal and  environmental. For further details about this evidence please see my website: https://www.affirmingevangelical.uk/made-gay )

Outside the church at least, the large majority of the UK public would no longer even question that some people are just born gay or bisexual. The annual British Social Attitudes Reports chart how people’s attitudes towards homosexuality have transformed over the past 40 years. In 1983 only 17% of the public agreed there "nothing wrong at all" with same-sex sexual relationships. By 2023 this had quadrupled to 67%. (See https://natcen.ac.uk/british-social-attitudes​)

But, just as  attitudes towards LGB individuals continue to soften, attitudes towards transgender people have considerably hardened recently. The same report found that in just the four short years between 2019 and 2023 the percentage admitting some prejudice against transgender people had doubled from 18% to 36%.

The polarisation of views about trans gender individuals was brought into sharp focus on 16 April 2025. That day the UK Supreme Court ruled that the definition of “sex” under the Equality Act 2010 simply meant the biological sex written on your birth certificate – male or female, regardless of what any later gender recognition certificate said . Many transgender people felt completely crushed by this decision (including one of my daughter’s close friends). Meanwhile, many "feminists" rejoiced that they believed it protected the safety of their women-only spaces.

Many defending the Supreme Court decision have argued that it’s a restoration of good old traditional common sense–before the progressives invented the dangerous fiction of transgender. It’s a return to the good old days when everyone agreed with the indisputable biological fact that we are all born male - if we’re born with a penis - or female - if we’re born with a vagina. After all, they say, it’s directly supported by the word of God Himself –  “male and female He created them.” (Genesis 1:27).

What our ancestors actually believed about sexual identities

But what did our ancestors actually believe about our gender identities? And what does scientific research now tell us about what causes people to identify as transgender? And what does the Bible have to say about all this?

The notion that our ancestors had always believed sex was simply male or female from birth would be a great surprise to the ancient physicians Hippocrates and Galen. They saw biological sex as not a simple binary of male or female sex but a spectrum between male and women with “many shades in between, including hermaphrodites, a perfect balance of male and female.”  (see Heavenly Hermaphrodites at https://share.google/6fE8UjiiNdn34pBBO )

And the original keepers of the God’s word, the ancient Hebrews, also acknowledged that biological sex was more complex. In their Talmud (their book of rules and interpretations supplementing Scripture) they recognized no less than seven different gender identities. These included : androgynous (having both male and female characteristics) and aylonit (identified female at birth without developing secondary female characteristics at puberty) (See The Seven Genders in the Talmud at https://share.google/ocaqRVeJyYCssNRGO )

It's very sad that our own society is less open, honest and accepting than they were about the reality of sexual and gender diversity. It could have avoided much harm to the small minority of intersex people born with mixed genitalia. Many were forced into “corrective” gender reassignment surgery as children because their parents felt compelled to squeeze them into the only two permissible gender boxes – male or female. It would have been much better in most cases to have left them with ambiguous genitalia and let them decide as they grew up how they chose to assign themselves – male, female or non-binary intersex. This difficult issue is explored in Jim Ambrose’s new documentary, The Secret of Me. (See https://www.theguardian.com/film/2025/oct/14/the-secret-of-me-review-documentary-tells-tragic-story-of-childhood-intersex-reassignment-surgery )

Does scientific research about causes of homosexuality offer any pointers to causes of transgender identities?

Over the past four decades a mountain of scientific research has built up all pointing to biology as the cause of our different sexualities. But what, if anything, does science now teach us about why some people identify with a different gender to the sex they were assigned at birth? Does the research into the causes of our sexuality offer any clues as to the causes for transgender identities?

To date, there have been far less scientific studies into the causes of transgender identities (aka gender dysphoria) than homosexuality. For example, a huge number of studies have now almost entirely ruled out social causes for homosexuality. But there has been relatively little exploration yet of whether there can be social causes of gender dysphoria. There is an at least plausible theory about social causes for “rapid onset gender dysphoria”, primarily experienced by adolescent natal girls. It’s as yet unproven but seems to warrant further study. (See “Gender dysphoria in adolescence: examining the rapid-onset hypothesis https://pmc.ncbi.nlm.nih.gov/articles/PMC11876199/ )

However, there is already plenty of evidence of biological causes for many people’s transgender identities. Some of this has been known about for centuries, some only much more recently.

Intersex - the reality of mixed genders and its causes

Just as chromosomal, genetic and hormonal variations affect our sexuality, they can also cause a small minority of people to be intersex - born with biological characteristics of both sexes. Despite what President Trump may declare, biological sex is not always straightforward nor necessarily binary. Whilst our sex is certainly not determined at conception, as Trump claimed, by the time we’re born the large majority of us are simply male with a penis and testes or female with a vagina and ovaries. But, occasionally, people can be a mix of the two. People who claim our biological sex is always binary male or female are just betraying their ignorance of the biological facts!

Studies have shown that up to about 0.5% of the world have mixed sexual or reproductive organs. That may not sound a lot, but globally that’s about 40 million people – about the population of Poland. (See the UN’s intersex fact sheet at https://www.ohchr.org/en/sexual-orientation-and-gender-identity/intersex-people See also, How sexually dimorphic are we? Review and synthesis at https://pubmed.ncbi.nlm.nih.gov/11534012/ ​)

Just as with the climate crisis, scientific facts do not change according to Presidential order!  

This issue was highlighted recently in the brilliant BAFTA-winning film Conclave. (Spolier alert if you’ve not yet watched it!) The right “man” ultimately elected Pope -  after the frontrunners are each exposed for their failings - turns out to be intersex. This person appeared to be a man but had a uterus and ovaries. This fact is only revealed to the previous dying Pope and the senior Cardinal overseeing the election of the new Pope. Both chose to keep this quiet because otherwise God’s chosen person for the job would be disqualified because his gender is not male but intersex and technically only a man can be Pope.

Although the character in Conclave was fictional, there are many people who have such mixed biology. It’s occasional but not rare. Sometimes - like the new Pope in Conclave - such people can look like a man or a woman externally, but internally – their organs, chromosomes, genetics or hormones – are more like the opposite sex. More rarely, their sex may be externally mixed - with ambiguous (“hermaphrodite”) genitalia, affecting between 1 in 2,000 and 1 in 4,500 of new born babies. (See “Disorders of Sex Development”, Selma Feldman Witchel (2018) https://pmc.ncbi.nlm.nih.gov/articles/PMC5866176/ )

If you search the internet, Youtube or TikToc you’ll find plenty of evidence of intersex people born with mixed external or internal genitalia, including:

·         those with a penis shaft and a vagina but no testes (and if you take off internet filters as you can actually see this with your own eyes)

·         those with a vagina and no penis shaft but with internal testes (see e.g. https://youtube.com/@blumekind )

·         those with a penis and testes but with internal ovaries or even a womb (as with the fictional Pope in Conclave)

But our biological sex is also about rather more than penises and testes and vaginas and ovaries. Based on biological testing, it’s estimated that up to about 1.2% of people have some intersex trait but without mixed sexual/reproductive organs. So, added to the estimated  0.5% with mixed reproductive organs, that means up to about 1.7% of the world are intersex. Globally, that’s about 136 million people – nearly the population of Russia – equivalent to about 1,500 people in a full Wembley Stadium crowd.

As microbiologist Dr Rebecca Helm writes on X, you may be genetically male or female, chromosomally male or female, hormonally male/female/ non-binary, with cells that may or may not hear the male/female/non-binary call, and all this leading to a body that can be male/non-binary/ female. This is partly because, although the starting point is an X and Y chromosome make you male and two X chromosomes make you female, “there is only one gene on the Y chromosome that really matters for sex. It’s called the SRY gene.” Sometimes during the embryo’s development “that SRY gene pops off the Y chromosome and over onto the X… A Y chromosome with no SRY gene means that physically you’re a female, chromosomally you’re a male (XY) and genetically you’re female (SRY).” And a similar thing can happen with two X chromosomes.  

Also, some genetic females produce more male hormones than some males do. And likewise some males produce more female hormones than some genetic females. Furthermore, for hormones to be effective the body cells need to hear them and sometimes those cells’ receptors get switched off. 

Why the facts about intersex matter for the trans debate

But what does that have to do with transgender people? Well, quite a lot actually.

Transgender individuals are those who identify with a different gender to the sex they were assigned at birth. Intersex individuals are those whose biological sex is in some way mixed. They are not the same thing but there’s a significant crossover. According to the 2021 census of England and Wales, 0.54% of people over 16 identified as transgender. The census didn’t ask if people were intersex. However, as we’ve seen, up to about 1.7% of individuals are estimated to be in some way intersex. That’s over three times the number identifying as transgender.

Many people with intersex variations will be unaware they are intersex. That’s because most variations are not externally visible. Furthermore, even where people were born with ambiguous genitalia, in the past sometimes this was surgically “corrected” soon after birth and then concealed from the individual. So, some will never be aware of this or may only become aware in later life. (This may explain why ancient Greeks and Hebrews were more aware of intersex identities than our immediate ancestors were - based on what their midwives told them)

I’m aware of no direct studies of this issue. However, logic and the above figures would suggest that many of the small minority who identify as transgender or non-binary likely do so because they’re one of the larger minority who are biologically intersex - even though they don’t know it.

As we’ve seen, most intersex people do not have mixed genitalia, but their internal organs, chromosomes or hormones may be partly or mostly like the sex opposite to what their genitalia suggests. However, like the fictional Pope in Conclave, unless and until they have the right biological tests they won't know.

A case in point is the former Bond girl, Caroline Cossey. (See https://en.wikipedia.org/wiki/Caroline_Cossey ).

Born as Barry Cossey, she had been assigned male at birth due to her external appearance. As far as everyone was concerned she was just a "normal" boy. However, instinctively she’d always felt like a woman. So, aged 17 she started hormone therapy and aged 20 had full gender reassignment surgery. She was labelled as a “transsexual” – or transgender as we would call it now – i.e. she identified with a different (female) gender to the (male) sex she’d been assigned at birth. But it was only just before her surgery that she had biological tests which showed she was not just transgender but also intersex. Despite her original male genitalia, chromosomally she was more female than male due to having a very rare XXXY combination of chromosomes. Although she has the normal single Y male chromosome she actually has more X chromosomes than most women! Her doctors were in no doubt that it was her mixed, but predominantly female, chromosomes which accounted for her identifying as a woman. Up to that point she had simply been labelled as transgender - identifying with a different gender to the sex on her birth certificate. She remained transgender, but the cause for this was now identified – she was intersex.  

In the early 1990s even as a very conservative evangelical opponent of same-sex relationships, I was struck by the sheer injustice of law and society failing to fully accept Caroline as a woman. I was anti-gay but pro-trans! Ironically, this is now the direct opposite position of an increasing number who are pro-gay but anti-trans.

Homosexuality and intersex - crossovers between LGB and TI

There also seems to be a significant crossover with the biological causes which make some people gay or bisexual.

Studies have consistently shown that more than half of intersex people identify as LGB+ (lesbian, gay, bi/pansexual) - a huge 69% according to a very recent EU wide study, published in September this year (See “Being intersex in the EU” | European Union Agency for Fundamental Rights https://share.google/aa0FGaCkAzpL3EdJ6 ) That’s over 20 times more than the mere 3% of the general population identifying as LGB+ on the last UK census!

It’s estimated that up to 1.7% of the population are intersex – about half the number identifying as LGB. So, even if only half of intersex people are LGB+, this would suggest about a quarter of gay and bisexual people may also be intersex. In reality it’s likely to be somewhat less because, of course, we only have data from the minority of intersex people who actually know they are intersex. A disproportionately large number of these are likely to have more obvious intersex characteristics which might increase the chances of them having a gay or bi-sexuality.

Clearly, the large majority of gay and bisexual people are not intersex. However, current scientific evidence now suggests that what causes gay or bisexual individuals to be that way is predominantly biology -  that they have a little more of the opposite sex thrown into biological mix or history. This might be due to the size of certain brain nuclei influencing sexual attraction in the womb, or numerous other reasons. The fact that same-sex attraction seems to nearly always have a biological cause may explain why, for example, anyone who has spent time with gay men will notice most of them show certain slightly feminine traits. This would fit with them having a minor variation to their biology that makes them very slightly more like a woman. The reverse is true of lesbian women.

Evidence from results of conversion therapies

A plethora of studies have now shown that  “conversion” therapies and treatments have been almost completely ineffective in “curing” people’s same-sex orientation and instead have done huge harm. (See my website, part four of The Answers: https://www.affirmingevangelical.uk/answers  ).

This is of course exactly what you’d expect if same-sex orientation is just part of an individual’s natural biology. Nothing has gone “wrong” with them; it’s just the way they were made. Neither medical science nor God are going to mend something that isn’t broken!

I haven’t directly explored studies of such “treatments ” for gender dysphoria. However, some of the studies I looked at considered “conversion therapies” for both sexuality and gender issues. Those studies found they were equally unsuccessful in “curing” gender dysphoria. If other studies bear this out then this seems to me a strong pointer that, like “homosexuality”, transgender identity probably also has a predominantly biological cause – it’s just the way some people are made. 

We don’t know what we don’t know …

Both Solomon and Socrates taught us that even the wisest of us actually know so little about life (Ecclesiastes 8:17).

About some things we know more than they did. But there is still a lot we don’t know about why people identify as trans gender. For many like Caroline Cossey it will be because they are intersex, even though they won’t know it until they have the right tests. For some it may be for other biological reasons, which we may be unable to test for currently. And yes, although not yet proven, it is possible that for a few there could be social environmental reasons.

It might also be the case that some straight, cis gender individuals, like myself, have bits of the other sex thrown into our own biological mix that perhaps makes us feel more in touch with our feminine or masculine “side”. But at the moment we just don’t have the scientific knowhow to identify those processes.

As the studies summarised on my website show, over the past 30+ years science has taught us so much about the biological causes for our sexuality. This has made many of the judgments I and others had previously expressed about the causes of "homosexuality" look rather foolish. Who's to say what science may teach us over the next 30 years about the causes for people's different gender identities? 

But what does Scripture teach us?

Genesis 1:27 tells us that in the beginning, “in the image of [himself] God created [human beings] …; male and female he created them.” As an evangelical Christian I do not believe science can disprove the truths of “God-breathed” Scripture. But, just as with earlier discoveries, science should inform the way we interpret God’s word over sex and sexuality. Where the science is clear, I believe, it should act as a corrective showing that previous literal interpretations were wrong and, rather than emulating the “flat-earthers”, we need to understand Scripture in a way that fits the facts. To do otherwise is to make our all-knowing God look foolish. It’s almost defaming God’s good name.  We should understand that Genesis 1:27 cannot possibly have meant that human beings are only ever binary male and female, because intersex people with mixed biological sexes are an established biological fact - just like the Earth revolving around the sun rather than the other way around - contrary to the original interpretation of e.g. Psalms 93 and Joshua 10:12-14.

Genesis 1:27 may mean humans were initially made simply male and female, and presumably heterosexual too (Adam and Eve certainly seemed to be and needed to be!). They were probably also black Africans. But God has allowed  humans to change and evolve since then into a mix of different colours and races and a mix of different genders and sexualities, too. But we’re still all humans made in his image.  

In describing humans as being created as "male and female", the writer was surely here using the common biblical literary device of merism - a way of saying "everything" by mentioning its different extremes. (See https://share.google/aHWkwCiusVV4mZQUT ). It’s very the same literary device he used earlier in this passage when talking of God creating "light" and "dark" and "land" and "sea".  The writer did not mean he didn't also create mixed shades of the different extremes; not just light and dark but dawn and dusk, not just land and sea but marsh and swamp land.

It’s the same when the prophet Joel talked about "young and old" (Joel 2:28). He wasn’t excluding the middle aged! but meant "everyone of every age". So, when he describes humans as created "male and female" this wasn’t meant to deny the existence of people who are a biological mix of the two. Indeed, their existence was fully recognised in the Jewish Talmud.

Genesis 1:27 surely shows that God's own nature spans the full breadth of what it means to be both male and female. Therefore, human beings are equally made in God's image, whether they are male or female or a mix of the two.

And in Matthew 19 our Lord himself seemed to describe a group of people who are born sexually different to most of us ; “eunuchs … born thus from their mother’s womb”.

And doesn’t this spectrum understanding of sexuality and gender fit with God’s design of his created order more generally? Not just black and white, night or day and day but the full colours of the rainbow light spectrum. Not just cats but European shorthair, Siamese, British longhair, Siamese and Manx. Not just dogs but German Shepherds, Labradors, Chihuahuas, Poodles and Yorkshire terriers. And surely such diversity should not be something to be fearful of but a wonderful thing to celebrate.

And aren't most of us biologically mixed up in different ways? It may have no impact on our sex or sexuality, but it may make us different to the supposed "normal" in other ways - affecting our mind, body or personality. I'm a very heterosexual/romantic, cis male but I can certainly see other variations to the "normal" in myself! And don't these myriad differences mostly come about from the complex biological processes through which God “knit us together in [our] mother’s womb”? And don't they make each of us “fearfully and wonderfully” and uniquely different?  We might bristle sometimes at the diversity, but I believe God actually loves and celebrates it.

We don’t yet have a full understanding of what causes people to identify with a different gender to the sex they were assigned at birth. We can’t yet rule out that for some their social environment might play a part in developing gender dysphoria.  However, it does seem that for many their gender dysphoria has a purely biological cause - they were born intersex -  a biological mix of male and female. For a few this will have been obvious from their mixed external sex organs. But for rather more, like Caroline Cossey, this will be due to internal biological processes happening before they were born, hidden to them unless and until they undergo the right tests. And for some those biological processes may be beyond science’s current knowledge or ability to test for it. The Bible is not a biology textbook, but, as we’ve seen, there is nothing in Scripture which denies the reality of intersex or transgender individuals, of which the ancient Hebrews and Greeks were well aware from their midwives’ testimonies.

For most of us our sex and gender identities are an integral part of our essential identity as human beings – even more so than our race, beliefs or sexuality. Therefore, to treat a small minority of people as if they were a different gender to the one they identify with, is likely to do them great psychological harmful, making them feel entirely undermined and oppressed. This is especially so when, after rigorous tests, the sex they identify with has supposedly been legally accepted by a gender recognition certificate. But this is what the Supreme court decision of 16 April 2025 did to transgender people. (A decision which the first transgender UK High Court judge, Victoria McCloud, is seeking to challenge through the European Court of Human Rights).

On the face of it, to treat this small minority of people that way is doing the very opposite of the one rule that our Lord tells us should dictate all our actions; “do unto others as you would have them do unto you.”  This is part of His ultimate law and test of love – to do what does good for people and avoids them harm (see e.g. Luke 6:9).

This is the same test which I argue must be used to decide whether to accept or reject same-sex marriage as aligning with God’s will (the basis for which I explore in my Tests section of my website. See: https://www.affirmingevangelical.uk/answers ). 

There might be justification to treat transgender people this way if the harm it did them was outweighed by the good it did or the harm it avoided to others. The anti-trans lobby argue that the Supreme Court does this. But it must be seriously questioned how it does so. Aside from the huge harm it does to transgender people, how does it actually make women any safer in their single-sex spaces? It cruelly bans from such spaces even trans women, like Victoria McCloud and Caroline Cossey, who have undergone full hormonal and surgical gender re-assignment. And it makes no difference if like Caroline they’re chromosomally more woman than man. And their hard-won gender recognition certificates are just torn in two. Yet at the same time this decision mandates that hairy, testosterone-fuelled trans men with their pump-actioned penises must use those ladies loos. How safe will that make women feel?

Meanwhile, research finds no evidence that transgender inclusive bathroom policies have resulted in increased assaults to women, other than trans women (or slightly masculine-looking women wrongly thought to be trans) being assaulted by cis gender women. (See e.g. the UCLA study referenced here: https://www.nbcnews.com/feature/nbc-out/no-link-between-trans-inclusive-policies-bathroom-safety-study-finds-n911106 )

This is not to say that there is some one-size fits all solution to all issues around trans gender people. The answer to whether trans gender women should be allowed to use female toilets may not be the same as to whether trans gender women should be allowed to complete as women in all professional sports.

The Myth of the anti-trans fundamentalists

There are some complex issues in the transgender debate, and there are both anti and pro trans fundamentalists who have turned this debate quite toxic. But I believe we need to be very wary of the anti-trans fundamentalists who deny all trans rights and enter this debate on a false premise: that sex is always binary and obvious, that all people are simply born male if they have a penis and testes and female if they have a vagina or ovaries. But as we’ve seen, some people are born with neither or a mix of both. Furthermore, microbiologists tell us that our sex and gender is determined by many other biological factors including our chromosomes and hormones. And there is much we simply don’t yet know.

And a huge warning sign hangs over the case of anti-trans fundamentalists: Donald J Trump, arguably the greatest anti trans fundamentalist, and possibly the greatest con man that the Western world has ever known. This is the same man whose greed-driven policies are killing millions by denying the well-established scientific fact of man-made climate change.

Whether it’s over trans issues, climate change, autism, vaccines, immigration, or Islam, Trump and his far right imitators in the UK and Europe happily distort the truth for their own ends. That end is to create mythical beasts that must be slain to “protect” ordinary folk. This creates fear, division or even hate. They use these issues as smoke and mirrors to distract us from the real things that threaten us and our world – especially the reckless greed of the super-rich which is such a key driver to climate change, the cost of living crisis, and global poverty.

I absolutely accept those sharing anti-trans views through social media are often decent people who genuinely believe what they're advocating is for the good of wider society. Mostly they are not seeking to harm or deceive anyone. But, I believe, some of them - the anti-trans fundamentalists - have been misled by powerful forces that exploit fear for political gain.

 Ultimately, as an evangelical Christian, I believe those malign powers go above and beyond the Trumps and Musks of this world. They themselves have been deceived by the devil, who deceives us all at some point (for sure including me!) Scripture tells us, the devil “prowls around like a roaring lion, seeking someone to devour” (1 Peter 5:8). As “the father of lies” (John 8:44) he does this primarily through his lies that deceive us into our own self-destruction. This has always been his tactic right from our beginning in the Garden of Eden (Genesis 2/3).

 I’m sure the devil finds it most amusing that he gives cover for the damage done by the rich and powerful of this world through pointing the finger at the most vulnerable and marginalised – like refugees and like racial, sexual and gender minorities -  the very sort of people our Lord most naturally aligns Himself with! (See e.g. Matthew 25:31-46).  It no doubt gives him even greater pleasure that in pointing the finger at such marginalised people he often does this in Jesus’s own name under the cover of the false religion of traditional “Christian” values or even “Christian nationalism” (a contradiction in terms if ever there was one!)

A Call to Love and Acceptance

Jesus naturally most aligns with the marginalized—refugees, racial minorities, and, yes, gender outsiders. To reject trans people is to reject those whom Christ embraces. Some transgender people might look slightly different to how we’re used to seeing men or women, just like same-sex couples look a bit different to traditional husbands and wives. But we need to accept people the way God has made them - “born thus … from their mother’s womb” – even where there’s something a bit different about them to what we might be used to - and celebrate the diversity! This is just part of Jesus’s command to “love (our) neighbours as (ourselves)” , treating others as we would want to be treated in their shoes, doing them good not harm. This overrides all other commands: “The commandments … are summed up in this one command: 'Love your neighbour as yourself.' Love does no harm to a neighbour. Therefore love is the fulfilment of the law.” (Romans 13:10).