Dear Rule and Raven,
I believe most Catholics, lay and cleric, assume that a properly formed conscience is always in harmony with the teaching of the magisterium and, therefore, a man in a same sex marriage is living in a state of sin.  I question the assumption.  For one thing, I believe the entire cosmos is theophany and that the sciences can tell us as much about the will of God as can Scripture.  What we read in the Bible is an account of how people have interpreted revelation and that interpretation is conditioned by what they already believed as taught and understood in their own cultures.  As our scientific understanding of humanity deepens through science, I believe we have to accept that past understandings do not represent the "Will of God" as much as the understanding (or misunderstanding) of humans.  It is high time to review the magisterium's  understanding in light of modern science as well as developments in the study of Scripture.