The ChrisTaliban believe that being gay is an abomination. This isn't an intellectual position, though they try to produce a (feeble) justification for it. It's felt viscerally, which is a lovely word and means "in your gut". They have a gut feel that it is evil and wrong. So why would they think this? Is it something we're born with?
Think about incest for a moment. There are powerful biological reasons why incest is a taboo. In almost all societies, parent-child and sibling incest is taboo. Inbreeding produces unhealthy offspring; unwell, mentally defective, stunted, short-lived. It would make evolutionary sense if there were innate guards against incest. And it seems there are. So an incest taboo represents not just custom but a genetic (innate) predisposition, a perfect example of the interaction between genes and culture.
Or murder. There is such a powerful taboo against murder that new soldiers have to specially trained to learn to kill. And they don't like doing it:
"It is a curious fact that the majority of soldiers, although well armed, never kill. During World War II, only one out of every five US soldiers actually fired at the enemy. The other four were plenty courageous, braving grave danger, landing on the beaches, rescuing comrades under fire, fetching ammunition for others [...] yet they failed to fire their weapons. One officer reported that 'squad leaders and platoon sergeants had to move up and down the firing line kicking men to get them to fire. We felt we were doing good to get two or three men out of a squad to fire.'" (Frans De Waal, The Age Of Empathy -- he gives several other examples)
Now, let's consider gayness. At first sight, if you're not thinking carefully, it might seem that gayness would obviously be a genetic taboo. After all, a gay man or woman is presumably less likely to produce offspring. Evolution would bias survival against those with a putative "gay gene". So if society has a taboo against gayness, this is, according the the ChrisTaliban, logical and obvious. Only, it isn't.
Whatever one's culture is, one is inclined to believe that the way things are in your society, in your family is the way things ought to be, the right way, the proper way. We in the West find it horrible if dogs or cats are maltreated ("It's just wrong!") but are quite happy to torture cows and sheepen and pigs so we can eat them ("Those animal rights people are extremists!") In India, however, killing cows is unthinkable. Forbidden. Cows are sacred. Eating animal flesh revolts them.
The ancient Israelites were few, and monotheists, surrounded by many other different polytheist cultures. They felt threatened. So they wanted to encourage population growth. Their priests told them to go forth and multiply. And they told men not to have sex with other men (not women, interestingly, because women were assumed to have little choice in sex or marriage, and would therefore reproduce willy-nilly). This proscription by the priests, written down as the Old Testament, was added to St Paul's distaste for the promiscuity he saw in the Hellenic world of Asia Minor and it became Christian dogma that being gay was wrong and evil, even though Jesus never mentions it.
So in cultures which have been influenced by a long Christian history or by recent Christian conversion, being gay, especially if you were male, became taboo. When I was growing up it was quite clear to me that being gay was worse than being a rapist or a murderer. Which is both absurd and clearly a taboo -- that fascinated horror when you do something "wrong". These values were exported to Africa and South America and Asia, overriding the more tolerant indigenous values, so that ironically today, as the West is just getting over its homosexuality taboo, Africa and Russia and Eastern Europe is on the whole getting more backward and narrow and less safe for gays. Encouraged and prodded of course by Christian crackpots.
But before Christianity/Judaism/Islam, in Europe and in Africa, homosexuality was tolerated and accepted. The Ancient Greeks, the Romans, the Persians, the Celts, the Teutons, Japan, China, India, Africa, Native Americans--all accepted one or more forms of gayness. It's only where Christianity and Islam have spread their message that gayness has become taboo, evil and unacceptable.
Mankind didn't survive as individuals wandering the African savannah. Everything about us indicates that we were members of groups of proto-humans dependent on each other for our survival. Just as we are now, only now our connections and dependencies stretch around the globe. Even today, a solitary hermit still depends to some extent on the products of civilisation (candles, oil lamps, salt, axes) and civilisation is nothing other than groups writ large. Even our intelligence appears to have evolved because as members of a group we needed to satisfy both our personal needs and those of the group. Empathy, sympathy, insight, self-sacrifice, love, companionship .... you name it, things we consider quintessentially human, these are essential to the survival of groups, but not of individuals. Without them humankind would not have reached where we are now. Without them we would not survive at all. Darwinian survival for us humans is not about individual survival but about the survival of the group. This is an essential insight, vitiating much of economics and politics and received wisdom in our own culture. When I board the train, or walk down the street, ppl do not fall upon me and rob me. Why not? Think about it. Don't take our broad human culture for granted. We have innate rules on how to behave. Because without them we would not be here. We would be orangutans, who are solitary, unsocial, and relentlessly heterosexual.
The taboo against incest is a logical one because of the damage that inbreeding produces. And incest doesn't just affect the individual, it affects the group. It makes the tribe/the group/the band less fit, less likely to survive, because the group supports its weaker members. Our ancestral small bands of proto-humans would have had enough problems with inbreeding anyway.
You might surmise that gayness would have been bred out of us. A Kinsey 6 bloke for example, would have no offspring, and so his genes would not be passed on (though it's true that in a tribe, his genes would still have been passed on by his fellows because the tribe would be somewhat related). But if gayness is such a genetic disadvantage, why are there so many of us?
It's only an apparent mystery, one that exists because we insist on a dualism: ppl are either gay or straight. Most gay-shaded people are bisexual. In fact I suspect a substantial chunk of so-called heterosexuals are actually bisexual, at least potentially. In the tribe, as a bisexual, your genes would still have been passed on to offspring. But your love for your fellow tribesman would have helped hold the group together. Actually, even if you were 100% gay and never had a child, you would still have helped your tribe be more fit, in a Darwinian sense, because you would have strengthened the ties within the tribe. Of course, the ChrisTaliban and the MusTaliban don't believe in evolution, so this explanation will not satisfy them. It is our intrinsic evil which makes us gay.
Everybody who has experienced it talks of the love that develops in war between members of the same corps, or about the love and comradeship which develops between the blokes in the same sports team. Team sports contests are of course substitutes for tribal warfare. Hunting dangerous animals would have required teamwork and sometimes, self-sacrifice. Anything that strengthened links within the team/group would have been beneficial for the team/group and therefore for its members. How else do you account for the one who gives up his life to save the many, and for how highly this behaviour is regarded by most cultures?
Far from being dysfunctional (as incest is) a measure of gayness added to our likelihood of survival. Because our survival was about the survival of our group, even more than it was about our survival as an individual. Except for the Abrahamic religions and the societies they have moulded, hatred of gays is not "innate". Even within them, the feeling "it's just wrong" has everything to do with culture and nothing with genetics.
Hatred of gays is not innate. It's taught, and can be untaught. As Nelson Mandela said, "people learn to hate, and if they learn to hate they can be taught to love, for love comes more naturally to the human heart than its opposite".