They sold flowers in airports, chanted on street corners, flew off to India and worked tirelessly to plant alternative religions in Judeo-Christian soil.
They also married and made babies.
While their parents were out spreading a counterculture gospel, the kids were left behind in nurseries, boarding schools and communal farms. Some felt abandoned and abused. Others blossomed.
Navigating the path to adulthood can be hard for any adolescent. But it can be an especially arduous journey for children in spiritual movements going through their own growing pains.
This series follows the lives of children born into four of the most infamous "youth cults" of the late 1960s, '70s and early '80s.
Founded by charismatic leaders in the 1950s and '60s, these four crusades burst onto the national consciousness during the "cult wars" of the '70s. Since then, they have struggled to overcome the foibles of their leaders, rehabilitate damaged reputations and gain acceptance in the larger religious community.
In 1950, a science-fiction writer named L. Ron Hubbard published a book called "Dianetics: The Modern Science of Mental Health," and gave birth to what would soon be known as the Church of Scientology.
Hubbard died in 1986, by which time his blend of marketing, psychotherapy and spiritualism had already grown into one of the era's wealthiest and most controversial movements.
In 1965, Srila Prabhupada, an aging Indian devotee of the Hindu god Krishna, came to New York to found the International Society for Krishna Consciousness.
By the time Prabhupada died in 1977, the Hare Krishnas controlled 100 ashrams, temples and farm communities around the world.
In 1968, David Berg, a minister with the Assemblies of God church in Southern California, started a Christian coffeehouse for hippies, the Light Club, where he encouraged the flower children of that era to get off drugs and into Jesus. Within a year, "Moses" Berg had become a polygamist and prophet of "free love," and had created the Children of God, an underground evangelical movement that survived his death in 1994.
All religions start as cults, spiritual movements rising around the revelations of a charismatic leader, or sects, revival movements breaking off from existing faiths.
American religious history is littered with the failed spiritual experiments of prophets, preachers and self-styled messiahs. Very few, as did prophet and polygamist Joseph Smith, the 19th century founder of the Mormon Church, start movements that evolve into mainstream faiths.
Whether they flourish or whither away, religious movements have a definite life cycle.
They start out intense and fanatical, convinced that the established religious and social order is misguided or corrupt. They have the way, the truth and the light.
Cults and sects can be harsh on apostates, and intolerant of dissent. Charismatic leaders may project their personal demons--as well as their spiritual insight-- onto followers through the double-edged sword of divine prophecy.
Others--such as the Peoples Temple of Jonestown, the Branch Davidians at Waco and Heaven's Gate in Southern California--fall into a paranoid spiral, burning out in an apocalyptic implosion of murder and mass suicide.
Two early tests facing new religious movements are how well they survive the death of their founder and whether they can pass the faith on to the next generation.
Reviving the spiritual fervor of the '60s and '70s has not been easy for the Moonies, the Hare Krishnas, the Church of Scientology or the Children of God.
Allegations of widespread child abuse have crippled the Hare Krishna movement and set back the Children of God's efforts to keep second-generation members in the fold.
Leaders of the Church of Scientology have put more emphasis on improving their public image and attracting new members, but are fighting off attacks from disgruntled defectors, investigative journalists and government officials.
Rev. Moon's Unification Church has tried the hardest to hold on to second- generation devotees, but has met with only limited success.
"They haven't captured the imagination of young people," said E. Burke Rochford, a professor of sociology and religion at Middlebury College in Vermont. "Children in these movements have not committed themselves like their parents did."
Rochford, a scholar of new religions, said he does not expect "a major world religion to come out of any of these movements, at least nothing like the success of the Mormons."
"But they did bring vitality and innovation into the religious landscape," he added. "They provided an alternative to the American mainstream."