In 2001, William Webb wrote an influential book called Slaves, Women & Homosexuals. In it, he argues that the Bible has a trajectory toward the abolition of slavery and the equality of men and women, but not the acceptability of same-sex love. And thus he argues that if we follow the trajectory set by the Bible, we are wrong to compare LGBT issues to these other emancipatory issues.
What Webb’s argument fails to see is that the Bible’s warrants against same-sex love are primarily based on the inequality of men and women. The understanding of nature/phusis presented in Leviticus and drawn on by Paul and other NT writers is a natural hierarchy, with men above women. (On this, see the fuller treatment here.) Webb is quite right that the trajectory of scripture moves away from that hierarchy, but misses what this means for same-sex love.
If the trajectory points away from the subjugation of women, it also points away from the parallel “proper sexual roles” of men and women. The emancipation of same-sex love (indeed, queer love in general) is thus as much a part of the liberation that Christ proclaimed in the Reign of God as the breaking of chains and the recognition of the equality of men and women in the image of God.