Does the New Testament condemn homosexual behavior as a sin? Are homosexuals going to hell?
The Core Question:
Looking at Leviticus and the old Testament in terms of this question is a straw person.
I would suggest looking what the New Testament might say on the topic. In considering that, you should at least consider this: Homosexuality in the New Testament
Romans 1 in the New Testament also is fairly clear on this point:
The Guilt of Humankind
18 For the wrath of God is revealed from heaven against all ungodliness and wickedness of those who by their wickedness suppress the truth. 19 For what can be known about God is plain to them, because God has shown it to them. 20 Ever since the creation of the world his eternal power and divine nature, invisible though they are, have been understood and seen through the things he has made. So they are without excuse; 21 for though they knew God, they did not honor him as God or give thanks to him, but they became futile in their thinking, and their senseless minds were darkened.22 Claiming to be wise, they became fools; 23 and they exchanged the glory of the immortal God for images resembling a mortal human being or birds or four-footed animals or reptiles.
24 Therefore God gave them up in the lusts of their hearts to impurity, to the degrading of their bodies among themselves, 25 because they exchanged the truth about God for a lie and worshiped and served the creature rather than the Creator, who is blessed forever! Amen.
26 For this reason God gave them up to degrading passions. Their women exchanged natural intercourse for unnatural,27 and in the same way also the men, giving up natural intercourse with women, were consumed with passion for one another. Men committed shameless acts with men and received in their own persons the due penalty for their error.
28 And since they did not see fit to acknowledge God, God gave them up to a debased mind and to things that should not be done. 29 They were filled with every kind of wickedness, evil, covetousness, malice. Full of envy, murder, strife, deceit, craftiness, they are gossips, 30 slanderers, God-haters,[f] insolent, haughty, boastful, inventors of evil, rebellious toward parents, 31 foolish, faithless, heartless, ruthless. 32 They know God’s decree, that those who practice such things deserve to die—yet they not only do them but even applaud others who practice them.
I’m not sure we can fully know the answer to the question with perhaps 100%–its not the type of wager however that I would like to personally take. Will Christian gays who have repented go to hell?
The Bible seems to suggest that anyone who is unrepentant of their sins will go to hell. So the Bible doesn’t per se single out gays.
Does the New Testament suggest that homosexuality is a sin?
Will God have grace on homosexuals who are otherwise committed in their heart to the principles of Jesus?
How does God view love and grace?
I’m not entirely sure.
Is gayness biological? Is it a choice?
Ethical considerations don’t necessarily speak to being predisposed to a particular type of behavior. Generally we think of ethics as separate from these considerations. A gene which might predispose one toward X behavior is not typically viewed as a means of escaping responsibility.
Should homosexuals avoid faith if the New Testament suggests their behavior or choices are sinful?
No. I don’t see why that would be the case either. There is certainly disagreement about this topic. Gods grace is certainly another issue. If I was gay….the verses in the New Testament would certainly give me pause in terms of thinking about my choices moving forward.