An estimated 10,000 live in neighboring Hillsdale, Utah; Colorado City, Ariz.; as well as in the Dakotas. Altman said his research showed that their family life was "as variable" as that in monogamous ones.
"We tend to stereotype all these families the same way, in their treatment of women and treatment of children, and that's not always the case," he said. "Our research suggests that abuse in these communities is no more than in communities at large."
Altman, who has worked on a review board for foster care, said the courts and media should not be so quick to judge these communities and feared many would be traumatized by the separations.
"Foster children in general have a tough time of it, and I imagine these kids do too," he said. "It may even be accentuated by the fact that all of a sudden they were wrenched from their families."
But those close to the Mormon community said these radical sects are a real threat to the welfare of their women and children.
Sandra Tanner, who was raised as a fifth-generation Mormon and is a direct descendant of Brigham Young, maintained that abuse is rooted in the polygamous culture of the church.
"These kids have been raised in an environment more controlling than the Amish," said Tanner, 67, who is the founder and president of the Utah Lighthouse Ministry, an evangelical Christian organization that opposes Mormon teachings.
"There is no question the children have been abused," said Tanner, whose own grandmother was a polygamist, living until the 1950s. She and her husband, raised in California, left the Church of Latter Day Saints after raising questions about teachings that "didn't add up."
"Many women in these polygamous groups talk about the emotional pressure put on young women to accept whomever the prophet says to marry," she said. "There is no love involved, and in some of these groups, the prophet has the power to trade off his wife to another man."
The youngest wives may be 13 or younger in some of the sects, according to Tanner. "They are raised to believe God requires it," she said.
"Part of the mentality is if you marry a girl young enough and she starts having children, she won't leave the group. She won't flee because she won't abandon her children."
But Tanner admitted that finding good homes for the 416 children posed a challenge. "They need to be in normal families," she said, adding that the mothers should be relocated outside the compound, as well.
"If they ever leave the group, they aren't prepared and they are isolated," she said. "It's horrific, and I cannot comprehend it."