LGBT activists argue that "homophobia" (which is their code for literally any disagreement with homosexuality what so ever) is just as bad as racism, sexism, or other forms of discrimination because "homosexuality isn't a choice". However, unlike race or gender, homosexuality is not a physical trait, but rather an action. You cannot choose your race or your gender (despite current transgender activism), but you can choose your behaviour.
If I were to fill a room with 10 people and asked you to tell me which ones were black, you could point that out easily. If I asked you to tell me which ones were women, you could tell me almost as easily. Race and gender are both distinguished by physical characteristics. But homosexuality is not. A gay person has absolutely no physical differences from any other human being. Rather than being distinguished from other people by physical traits, gay people are distinguished by their behaviour.
But what causes the behaviour? Is it inborn, or is it to do with our experiences? Two key pieces of evidence lead us towards the latter. The first is monozygotic (identical) twins. The Bailey Pillard study was published in 1991. The results of the experiment were overwhelmingly positive for Christianity. Specifically, monozygotic (identical) twins were only both gay 50% of the time. Monozygotic twins share exactly the same DNA. If homosexuality was as inborn a trait as race or gender, there shouldn't be a single case of a gay identical twin with a straight twin.
The second proof that it's not an inborn trait is the transition between sexuality. People change from gay to straight, or from straight to gay a lot. I personally knew a girl who was straight for a long time, even having a boyfriend, who eventually turned lesbian. She's the only example I know of a straight person turning gay, but I myself am an ex-gay. I am far from the most impressive example. David Kyle Foster is a better one. In his own words, "To those who suggest that I never was homosexual, my response is, "Does sleeping with over 1,000 men count?"" I am quite grateful to God that I never reached 1,000 men, but I can sympathise with the claims that he was never gay. The idea that homosexuality is immutable is so strong in gay philosophy that ex-gays, it is claimed, simply do not exist. In the minds of an activist, you are either gay, and can never stop, or the fact that you stopped means you cannot have been truly gay. This is known as the "No True Scotsman" fallacy.
But let's suppose homosexuality is an inborn trait. After all, mental illness does exist, and it's not distinguished by any physical trait, so we'll just place homosexuality in the same category and ignore all the proof that it isn't inborn. Would that make homosexuality ok? The nature/nurture debate has raged for centuries (no thanks to Evolution). What makes us behave a certain way? The question is, should we actually care? If tomorrow it came to light that paedophilia is a desire we're born with, would that be ok? What about theft? Rape? Murder? Bestiality? All of these things, regardless of whether or not we are born with the desire, are inherently evil acts for which we are justly punished if we carry them out. This is because a desire, even if it is inborn, does not have to be acted upon.
An excellent example of this is David Wood. David Wood is a certified sociopath. He is literally incapable of feeling normal human emotion. He was still put in prison for attempting to murder his dad. However, David Wood has since become a Christian. He is still a sociopath. He is still incapable of normal human emotion. But I remember him telling a story about how while in prison, some of his fellow prisoners theorised that he was in prison because he defended a woman's honour, only because he was too nice to have been convicted of anything truly evil. If a certified sociopath can live for God, why can't a gay person?
Yet still activists cling to this notion that homosexuality isn't bad because it's not a choice. But it is. If you don't have a choice about who you're having sex with, that's called rape.
Whether born gay, or turned gay by experience, one thing is certain: We are all born sinners. But we're not called to behave as we're born. We're called to be born again. We're called to abandon our sinful nature in favour of a new nature. A Godly nature. Homosexuality, part of our old nature, is not worth the punishment it brings with it. Heaven is certainly worth leaving the gay life behind. I'm going to give you a piece of advice that is highly unpopular, but highly beneficial: Repent. Repent not just of homosexuality, but of all the sin in your life. Every evil deed, every vicious word, ever idle thought, these are all things that keep us separated from God, and will eventually condemn us to Hell. But Jesus provided a way out. He took the full wrath of God on our behalf, so if we repent, we no longer have to. I strongly urge you to take that free gift.