To date, scientists, psychologists and sociologists have been unable to determine what causes a person to be homosexual. There is no evidence of whether genes cause someone to born as a homosexual, whether one becomes that way in the womb due to hormones and other such factors, whether one becomes that way during early childhood development or during some time later due to environment, or whether it is some combination of all these. At least one gay activist does not think it is solely due to genes and hormones (http://www.onenewsnow.com/Culture/Default.aspx?id=205608). However, that is not the point of this post.
There are people who believe that, if science can ever prove that people with a homosexual bent are born that way, they will no longer be told by christians that they should not have homosexual sex.
But these people do so in ignorance of the difference between how a person is born and what a person does. Whether one is born with a nature where they will eventually have homosexual desires, or not, is irrelevant. Whether one is born with a predisposition towards being a drunkard, or any other sin, or not, is irrelevant. Whether one is born blind or with sight, whether one is with some deformity or healthy, whether one is born white or brown or any other hue is irrelevant. What matters is not how one is born.
What matters is whether one has faith and what one does. Do you believe in God (Acts 16:34). Do you love God (Deuteronomy 6:5; Matthew 22:37)? Do you believe God (James 2:23)? Do you have faith that Christ suffered and died for your sins, as we need to have to be saved (John 3:16)? Do you obey God (Luke 11:28; Acts 5:29)? Do you choose to change from sinning and turn to God and show your change through how you live your life (acts 26:20)? Do you choose to not indulge the sinful nature, as we are told to do in Galatians 5:13? Do you choose to take every thought captive to make it obedient to Christ, as we are told to do in 2 Corinthians 10:5? The last two things are simply the obedience to God we are told to have (John 14:15-24), which give evidence of the repentance from sin to God which we are told to have (Acts 26:20). These are things that matter – not how one was born.
We must believe there IS a God. We must believe God. We must love God. We must have faith in Christ, who died to pay the penalty for our sins. If it is truly faith (rather than merely an idea or a belief), it will endure and simultaneously cause us to walk away from sin and towards God. Not all sinful desires or ways will immediately leave us, but the walk towards God will have begun. And if it is truly faith, it will continue to the end. And that end will entail us being with God in heaven.