Are people born gay? A lot of people either from, or sympathetic to, LGBT activist groups would say yes, homosexuality is something that is inborn. At the very least, they claim, it's not a choice.
Ultimately, regardless of the answer, the question itself is irrelevant. God doesn't tell us to behave according to how we were born, He tells us to be born again. We're told that our flesh is weak, but we're not supposed to worship Him in the flesh, but in the spirit.
A similar concept exists in secular society. Ignoring the constant infighting within LGBT activism, how many people would advocate emptying prisons if it could be demonstrated tomorrow that murderers are born murderers? Rapists are born rapists? Pedophiles are born pedophiles? Even if these twisted desires have some form of inborn origins, any sane person would admit they are evil and should be avoided.
The Bible doesn't give any indication that we will be free of evil desires on this side of eternity. On the contrary, it assumes we will have sinful desires, even saying we're lying if we say we have no sin (1 John 1:8-10). Temptation comes when we are drawn away by our own desires (James 1:14). So James here draws a line between desire and temptation. Verse 15 even draws another line between temptation and actual sin.
So, what if we are born with homosexual desires? It's completely irrelevant because we need to draw ourselves away from those desires before they lead to temptation. If you have a sinful desire, you don't have to act on it.
In 1 Corinthians 10:13, Paul tells us there is no temptation you can face that isn't common to humanity. In fact, God is so faithful that He won't even let you face temptation unless you are able to face it, and He will provide a way out. What that means for someone who believes that they were born gay is that even if that were true (it isn't), even if there was some gene they possess that gives them homosexual desires (there isn't), these desires are not so strong that they cannot overcome it. It's not like the only course of action available is to act on this desire.
There is no evidence that anyone is born gay, but what the Bible does say is that we are all born sinners (Psalm 51:5; 1 Corinthians 15:22). That includes straight people. Homosexuality is a sin, it is not the sin. According to Jesus, a man looking at a woman with lust has committed adultery with her in his heart (Matthew 5:27-28).
So let's put all this together and apply it to a situation I personally experienced just this afternoon. Whatever my sexual orientation has been in the past (and it has fluctuated), I know that I was born a sinner (Psalm 51:5), having inherited Adam's curse (1 Corinthians 15:22). God Himself doesn't tempt me (James 1:13), but I do have sinful desires, which I can either control, or allow them to control me (James 1:14-15). There are no forms of temptation I can experience which no human has ever experienced, and when temptation comes, God will provide a way out (1 Corinthians 10:13).
Currently, I am straight. There is nothing that guarantees I will never again have a homosexual desire, but as it stands, my sexual desires center around women. So, as I waited to board a bus this afternoon, I encountered a dangerous situation. In the queue just in front of me was a very attractive young woman who was immodestly dressed. Despite my personal faith, nothing in the Bible promises I will never desire to look upon such women with lust, which we've established is a sin.
However, desire itself is not sin. We are tempted when we are drawn away by our desire, and that produces sin (James 1:14-15). It would have been easy to allow myself to be tempted at this point. All it would take is for me to move my eyes in a certain direction. But God has promised to provide a way out of our temptation (1 Corinthians 10:13). I did not have to sin in this instance. Rather than looking at the woman, I focused intently on the bus.
By the logic of "I was born that way", most straight men are excused from the commands of Jesus. Let's be honest here: If not for the commands of Jesus, we wouldn't even know it's wrong to do these things. Unbelievers have some sexual morals, but they generally don't resemble Christian morality. They certainly wouldn't avoid looking at someone they find attractive with lust. In fact, in my experience, unbelievers tend to say "it's ok to look". In other words, a straight unbeliever is born with the same tendency to not follow God's commands as any gay person could ever claim to be. Just as straight people are told to deny their own sinful nature and avoid sexual immorality, so also are gay people told to deny their sinful nature and avoid sexual immorality.
Therefore, whether we believe gay people are born gay, or we believe the science that says they are not, homosexuality remains a sin, and will be judged as any other sin will be. We aren't told to behave as we were born, but to be born again. Those who are born again, while they remain on Earth, will still struggle with sin, yet in Christ, they have the power to overcome, and will be forgiven even if they fall.