The concerns about the next generation of Moonies start at the top, with the sons of the Rev. Sun Myung Moon.
In 1998, Moon's former daughter-in-law, Nansook Hong, published a tell-all memoir about her turbulent 14-year marriage with the self-proclaimed messiah's eldest son, Hyo Jin Moon.
Entitled "In the Shadow of the Moons," she accused the onetime heir to Moon's spiritual and financial empire of alcoholism, cocaine abuse, wife beating and cavorting with prostitutes.
Then, in October 1999, one of Moon's other sons, Phillip Youngjin Moon, 21, committed suicide by jumping from a 17th-story balcony at Harrah's hotel in Reno.
Both events are more than personal tragedies. They strike at the heart of Unification Church theology.
Moon, 80, teaches that he and his wife are the True Parents of a new spiritual lineage born without original sin.
Some Unification Church leaders say problems in Moon's own family have troubled rank-and-file Moonies.
"Many members have been disappointed," said national church Treasurer Michael Inglis. "It challenges some people's faith."
The Rev. Beno Leal, an associate minister with the Unification Church in the East Bay, said Moon's children may have been born without original sin but that doesn't mean they're perfect.
"Adam and Eve were born without original sin, but as we know, things can still happen if you make a mistake," Leal said. "Rev. Moon sacrificed his own children when he was out building the church. We believe there are evil spirits in the world. Those kids are spiritually under siege."
Given the troubles surrounding his eldest son, Moon is grooming his third eldest male child, Hyun Jin Nim, as his successor.
Last year, the Unification Church published a history of its U.S. ministry, "40 Years in America," and it ends with the clear anointing of Hyun Jin Nim, a graduate of Harvard Business School.
In the book's final chapter, Nim admits that many children of Moonie parents "have become disillusioned and have fallen astray." He promises "to revive the second generation of our movement as well as offer a fresh new vision for the world's youth."