http://publicreligion.org/2011/10/millennials-leave-their-churches-over-science-lesbian-gay-issues/

The study udentified six main reasons:

1. a sense that young adults were receiving an unsatisfying or “shallow” version of Christianity
2. feelings that the church was overprotective
3.the perception of judgmental attitudes around sex and sexuality
4. churches’ unfriendliness to members grappling with doubt
5. the sense that Christianity was too exclusive
6. finally, the tense relationship between Christianity and science.

According to the study, 73% of white mainline Protestants say that they would continue to attend their church if it decided to bless gay and lesbian couples.