Let's just say that they don't want to be gay... They've been praying for years about it alone and with others asking God to change them. So they certainly did NOT choose it
So because they want to change, but can't (because this stuff is 90%of the time determined with birth), ask God to help them, live a good christian life and resist the temptation they aren't/can't be Christian? That's something that doesn't sound right...
You are talking about temptation. You are not the only person whos being tempted, everyone you see on this forum is dealing with these things as well. Not the exact same urges, but they do deal with urges of sexual immorality as well in their own way.
Jesus was tempted in the desert, but He said no and obeyed the word of God. We are to be like Him. Is it a sin that we are being urged and pushed to do what we know we shouldnt? No : p God is allowing these things to happen as a test to see who will come to Him and who will do what they please. It is a sin to give into these urges and follow them, though. And you and I have both given into them at some point, in some way. That is why He gave Himself on the cross for our sins.
I can promise you that it is entirely possible to live a happy life without giving into these urges : p You are not alone in this struggle, there are many Christians out there who deal with this. We do not choose to be urged towards something we know is wrong, but we DO make the choice to follow it. And that is where the word of God tells us we are held accountable for it.
Temptation can be tough at times, for all of us. But we do have the power to say no and keep our hearts on God. I feel like, though occasionally stressful at times, I live a happy life without acting out on these urges : p And I can tell you that if you are willing to change your heart from living for personal fulfillment to living to do whats right, you can feel at peace too.