There's a fairly new Christian interpretive technique called  Redemptive Movement Hermeneutic (RMH). The idea is best expressed in the book 'Slaves, Women & Homosexuals: Exploring the Hermeneutics of Cultural Analysis' by William Webb.

To summarize it, RMH is an attempt by leftist Christians to reconcile obvious confrontations between modern liberal egalitarianism and Christianity. Proponents of RMH argue that God allows humanity to evolve over time on issues like women's roles in the Church, slavery, and homosexuality.

For example, in the Old Testament God clearly endorsed race based chattel slavery. He even personally established it in Leviticus 25:44-46 (he called slaves "property"). In the New Testament, RMH advocates say God softened this to the point that slaves were supposed to be treated as subjugated brothers. Today, God wants us to evolve again on the issue, override everything in the Bible, and preach that slavery is an abhorrent abomination that should be discarded entirely.

This same kind of progressive thought is repeated in the case of both homosexuals and women. Women were chattel in the Old Testament, silent sisters in the New, and now we should accept them as fully equals to men and let them hold leadership roles in the church. Homosexuals were stoned in the Old Testament, discouraged in the New, and now we should embrace homosexual marriage.

The problem with the RMH hermeneutic is that it suggests man can change the Bible's teachings based on what he thinks God might want. It suggests man can read God's mind and predict his desire for man to "evolve" on moral questions.

When God wanted man to evolve in the past, however, he produced miraculous signs to demonstrate it (the plagues, Mount Sinai, Christ's resurrection, etc.). The only sign given in modern America recently is the near miraculous apostasy of about half the Church on the homosexual marriage question.

For nearly two thousand years, the church stuck to a general consensus about women leadership, homosexuality, and, arguably, slavery (opinons about slavery started shifting somewhat earlier than other issues). Why should we accept that man suddenly expected to evolve on these issues? The timing is off. The most likely explanation for the ascendance of the RMH hermeneutic is that it allows Christians to strike a peaceable compact with contemporary liberal society. I doubt God would appreciate such an unholy alliance.