Renowned evangelist Billy Graham recently shared his thoughts regarding a far-too-common question: What causes an individual raised in a good Christian home to leave the faith as an adult?

"People turn away from their childhood faith for various reasons, I've found," Graham, 97, wrote in response to such a question shared with The Kansas City Star.

Sometimes, people simply get too preoccupied with other things, become too involved with non-Christians, or simply decide that faith has no place in the life of an intelligent adult.

However, ultimately, people turn away from the faith for two basic reasons, the evangelist argues.

"First, their faith was too shallow, and it lacked any real commitment," he writes. "Children may not understand everything - but they can understand that God loves them, and Jesus Christ came into the world to offer them the gift of eternal life."

He adds, "Moreover, they can understand that they need to commit their lives to Jesus by inviting him to come into their lives. Faith and commitment go hand in hand."

Second, people may reject their childhood faith because they never truly understood that faith needs to grow.

"Like the seed in one of Jesus' parables, a plant with no roots eventually withers and dies - and the same is true of faith," Graham explains. "Jesus said, 'They believe for a while, but in the time of testing they fall away' (Luke 8:13)."

The pastor concludes his thoughts by urging Christians to pray for the children in their individual churches: "[Pray] that they'll make a clear commitment to Jesus and then grow stronger through the Bible, prayer, and fellowship with older believers."

A 2015 Pew Research Center survey of 35,000 American adults found that more than one-third of millennials now say they are unaffiliated with any faith, up ten percentage points since 2007.

"It's not as if young people today are being raised in a way completely different from Christianity," said Greg Smith, Pew's associate director of religion research and the lead researcher on the new study. "But as adults they are simply dropping that part of their identity."

Throughout his long career, Graham has often shared his thoughts on how parents can raise their children to fear the Lord. In August 1955, the pastor wrote an op-ed for Decision magazine titled "Raising Children in a Godless Age" offering parents advice that is still relevant today.

Graham, who has five children and 19 grandchildren, emphasized that parents must spend time with their children, set a good example for them, discipline them, and teach them to "know God."

"If you fail to discipline your children, you are breaking the laws, commandments and statutes of God," he said. "You are guilty not only of injuring the moral, spiritual and physical lives of your children, but of sinning against God. The Bible says that if you fail to discipline your children, you actually hate them."

The best way to influence your children, he added, is to set a good example because "the majority of children acquire the characteristics and habits of their parents."

As for teaching your children to know God, Graham said, "Very seldom do parents have trouble with children when the Bible is read regularly in the home, grace is said at the table and family prayers take place daily. Most trouble with teenagers comes from children reared in homes where prayer is neglected, the Bible is never opened and church attendance is spasmodic. Christ gives the moral stability, understanding, wisdom and patience needed to rear children."

There is only one solution to combating the problems afflicting young people, explained the pastor, and that answer is Christ:  "Christ in the home, in the lives of the parents, is the only permanent solution to the menacing teenage social problems in America."

Church every Sunday and daily prayer "will solve 90 percent of the problems you have with your children," he concluded.

For teens who want true joy and happiness, and not the temporary intoxications of today's sinful culture, they should turn to Jesus Christ. He "can give you the greatest happiness, the greatest adventure and the greatest thrills you have ever known," Graham said.