Can you awesome Bible scholars definitively lay out for me, using scripture, why being gay is not a sin?

I am firmly of the belief that homosexuality is great and there's nothing wrong with it. But I get intimidated when challenged on this by more conservative Christians, and suddenly I forget any scripture or argument which I can back myself up with, other than a general "God wants us to love each other".

Can some of you give some legit points which help prove that the Christian faith can and should be accepting of gayness? Thanks.