Texas child welfare attorneys say children were removed from the YFZ Ranch and should not return there because its residents live as one big family and all have the same dangerous belief system.

The agency that has taken legal custody of 464 children sent its response Thursday to a petition from dozens of Fundamentalist LDS Church mothers. The petition asks the Texas 3rd Court of Appeals to order Judge Barbara Walther to return the children to their mothers.

"The community has one common belief system that young girls are called on to be wives and no age is too young to be married," wrote Texas Department of Family and Protective Services attorneys. Some adults and children at the ranch described it as "one large community," even though there are several houses at the complex.

"All of the women are called mothers to all of the children in the home, and the children call each other brothers and sisters," the response states.

When a victim of abuse is found inside a home, child welfare investigators have concerns for all of the children in that home. The court filing also states that a polygamous environment "would make a 15- or 16-year-old child highly vulnerable to individuals who are willing to exploit them and take advantage of their child-like qualities."

Previous court rulings have determined that it isn't necessary to prove that a parent personally abused his or her own child in order to show that a child is in danger, the court documents state.

Texas officials say several teens at the ranch were either pregnant or had children when they were underage. As for the boys and younger children, the agency argues says they are still in danger if allowed to continue living in that environment.

The new filing refers the appeals court to testimony from child psychiatrist Bruce Perry, who described an "unhealthy" belief that it's OK to have sex with and marry young women. "This pervasive practice and belief creates an environment that develops people who have a high potential of replicating sexual abuse of young children as a part of their belief system," the court document states.

"Part of the danger to the boys is that their belief system requires that they follow the prophet," it also stated.

The original petition to the Court of Appeals was filed on behalf of 38 women by Texas RioGrande Legal Aid attorneys. Those attorneys filed a response late Friday to DFPS' response, arguing that DFPS has no evidence or legal authority to treat the entire 1,700-acre ranch as one household.

"The department attempts to justify the mass separation of every single child from the YFZ Ranch from his or her mother on the ground of 'systematic and institutionalized sexual abuse of children.' That is a very strong allegation, yet it is not supported by sufficient evidence," attorneys for TRLA write.