Churches are worried, and with good reason.  A new study from the Hartford Institute for Religion Research released last week reported that over the past decade, America’s congregations have lost members and suffered a decrease in “spiritual vitality,” brought on, in part, by ageing congregations. And the Barna Group, a Christian-affiliated polling organization, recently completed a five-year project which has morphed into a book called You Lost Me: Why Young Christians are Leaving Church and Rethinking Church.

The study focused on young adults who were regular Christian churchgoers during their early teenage years, but became disconnected from church life after the age of 15.  According to Barna, 59% of young Christians disengage either permanently or for an extended period of time from church life around this age.  There was, predictably, no single reason for young adults’ disaffection with the churches where they grew up.  But the study managed to isolate six main reasons why Millennials (age 18-29) tend to leave Christian churches as they grow up: a sense that young adults were receiving an unsatisfying or “shallow” version of Christianity, feelings that the church was overprotective, the perception of judgmental attitudes around sex and sexuality, churches’ unfriendliness to members grappling with doubt, the sense that Christianity was too exclusive, and finally, the tense relationship between Christianity and science.

PRRI has also pointed to several of these issues over the past few months.  For example, as Dr. Robert P. Jones pointed in a recent piece for the CNN Belief Blog, our recent survey on evolution and climate change showed that 64% of Millennials say that scientists generally agree that humans evolved over time, compared with 32% of seniors. Likewise, 42% of Millennials believe that scientists agree the Earth is getting warmer because of human activity, compared with 30% of seniors.  The strain here is apparent: one-quarter of Barna’s respondents said that “Christianity is anti-science,” while an additional 23% said they have been “turned off by the creation-versus-evolution debate.”

But buried within Barna’s category of “sex and sexuality” is something quite specific: churches’ stances on gay and lesbian issues.  Research from earlier this summer reveals that nearly 7-in-10 (69%) Millennials agree that religious groups are alienating young people by being too judgmental about these issues.  Only 37% of seniors agree.

So what will convince young adults to come back to their churches?  Our report, Doing Church and Doing Justice: A Portrait of Millennials at Middle Church, explores the religious lives of 25 young adults who have maintained a connection to local religious communities.  What they wanted in a church was a community that encouraged social justice activism, a place of creativity and critical thinking, and a space free from judgment.  Perhaps most important, Millennials felt that churches should “focus their engagement on actions that serve the common good or speak up for the oppressed rather than opposing a controversial issue because of theological objections.”

These interviews speak volumes about what Millennials want from religious communities.  But Barna’s latest survey shows that congregations will need to be willing to have conversations and make changes that could be jarring for many seniors anchoring their communities before they can coax Millennials back into the pews.