It's Not A Sin
Calling homosexuality a sin is a bad interpretation of scripture. In recent decades, more theologians have come to a better understanding of scripture -- one that does not condemn same-sex relationships.
Theologian David Gushee, Rachel Held Evans, Tony Campolo and many more have renounced their condemnation of same-sex relationships. Instead, opting for theology that affirms LGBT individuals the way God made them.
Resource for affirming interpretations of scripture:
God & The Gay Christian by Matthew Vines
Changing Our Mind by David Gushee
Bible, Gender, and Sexuality by James Brownson