Why young adults leave the church is one of the most vexing questions facing the church today. A 2007 LifeWay Christian Resources survey indicated that 70 percent of 18–22 year-olds stop attending church for at least one year. Furthermore, Barna surveys have repeatedly shown that a majority of 20 year-olds leave church, often never to return.
Sam Eaton cites twelve reasons millennials are leaving the church. Causation for young adults exiting the church has been studied for decades, yet little has been accomplished by way of reversing it. As a gospel preacher, seminary president, and father of five young children, this is more than a theoretical concern. At risk of being overly simplistic, I want to suggest three additional factors that are often overlooked in this discussion.
Many Young Adults Leave the Church because They Never Joined it Spiritually
Many young adults leave the church because they were never truly converted to Christ in the first place. John the Apostle warned us “They went out from us because they were never of us; for if they had been of us, they would have no doubt continued with us" (1 John 2:19). And in his Sermon on the Mount, Jesus soberly warns, “Not everyone who says to me ‘Lord, Lord!’ will enter the kingdom of heaven; but he who does the will of my father in heaven" (Matthew 7:21).
In fact, this is a troubling, but recurring, theme throughout the New Testament. Jesus frequently warned of pseudo converts, most memorably in his parables of the four soils, the wheat and the tares, and the sheep and the goats. This grievous occurrence is why Paul exhorted the Corinthian church to “examine yourselves to determine whether you be in the faith" (2 Corinthians 13:5)
This predicament is as old as the church itself, and it is no respecter of age. Young adults have not cornered the market on unregenerate church membership, but with so many other pressures and opportunities associated with their life stage, their exit ramp is more predictable and more pronounced. In other words, young adults are just one bloated demographic slice of an ever-present challenge within the church today: unregenerate church membership.
Many Young Adults Leave the Church because They Never Experienced it Corporately
To their own detriment, too many churches function like a confederation of para-church ministries meeting under the same roof. For instance, many young adults traveled from children’s church, to children’s ministry, to the youth group, and then to college ministry. Amazingly, many young adults spend 20-plus years in a local church with the congregation as a whole always being an ancillary group, and with their predominant religious attention focused from one of the church’s subgroups to the next.
Age-graded and targeted ministries can be healthy in as much as they undergird the life of the church and facilitate strategic discipleship and family ministry. But when they displace the central and formative place of congregational worship and corporate gatherings as a whole, they prove detrimental to both the individual and the local church. In fact, the beauty of the New Testament church is its homogeneous diversity: Jew and Gentile, young and old, rich and poor, all united by the gospel and gathered around the common ministry of the Word, the Lord’s table, prayer, and fellowship, together as the body of Christ.
There is a sweetness in God’s people, and we rob our children of experiences of God’s grace when we neglect to incorporate them into the corporate body. It is for this reason I want my children to know the saintly widow seated behind them and the contemporary adult couple seated in front of them as well as they know the children in their own classes.
When they are disconnected from the congregation, it should not surprise us that young adults, who have never known the church as a whole, are disinclined to embrace it when their age-graded group has run its course. Do you want your children to participate in the church when they become adults? Then cultivate their participation as they travel life towards adulthood.
Many Young Adults Leave the Church because They Never Came to Love it Personally
Though the church is not perfect, it ought to be cherished, warts and all, by every member of the congregation, including our children. As parents, we cultivate this by esteeming the church—and the individuals who comprise it—before our children. As a parent, my wife and I have long since covenanted together to guard our tongues, especially before our children, about the ministers and members of the churches we have joined.
Granted, no church is perfect, and if you ever find the perfect church, do not join it, or you will likely ruin it. At the same time, a spirit of criticism and sarcasm about the pastor and other members of the congregation mark the homes of too many church members. In so doing, children are hearing reason after reason why they should doubt the Word of God, not value fellowship of the saints, and be indifferent toward gathering with God’s people. When this occurs, why should young adults commit their lives, time, and resources to a pastor and group of people they have overheard their parents repeatedly denigrate?
Why do young adults leave the church? This is a pressing concern, but an often-misplaced question. Instead of focusing so much on why young adults leave the church, let’s focus more on how they enter the church and how they engage it along the way. And, when you show me young adults who are truly converted, have ministered and worshiped with the church as a whole, and have grown to love the people of God, I will show you young adults who are a lot less likely to depart the church anytime soon.
 See Scott McConnell, “LifeWay Research Finds 18- to 22-Year-Olds Drop out of Church.”
 See, for example, The Barna Group, Ltd., “Most Twentysomethings Put Christianity on the Shelf Following Spiritually Active Teen Years”