RICHMOND -- Parents should not have to relinquish custody of severely mentally ill children to access public funds for mental health treatment, Attorney General Bob McDonnell declared in an advisory opinion issued Wednesday.

McDonnell's opinion addresses what he described as "wrenching and potentially tragic situations" in which parents surrender custody of mentally ill children to the state for treatment that families cannot afford.

McDonnell said the Comprehensive Services Act for At-Risk Youth and Families allows families access to services without forcing them to give up custody of their children.

Many Virginia localities have interpreted the act differently, determining that parents can ensure mental health services only by signing an agreement with the Department of Social Services relinquishing custody of the child. Mental health services are mandated for children in foster care under the Comprehensive Services Act.

McDonnell said such a choice "infringes upon the compelling state interest in supporting and maintaining the family unit."

"It is inconceivable that the best way to provide such services to a child and his family is by an interpretation that tears the family asunder," McDonnell wrote in his nine-page opinion.

McDonnell issued the opinion at the request of Del. William Fralin, R-Roanoke, who has sponsored legislation in the past two years to eliminate the need for relinquishing custody.

Fralin said he introduced the legislation after reading news accounts of families that were torn by a choice of giving up custody of a mentally ill child or not seeking services the child needs. Fralin said he has not decided whether to introduce a similar bill next year.

"This may fix the problem," Fralin said of McDonnell's opinion.

Budget analysts who reviewed Fralin's bill said the cost of his proposal is difficult to determine because there is no way to estimate the number of families who would access services if they could retain custody of their children. State and local governments would spend about $30,000 annually on each case, according to the analysis.

As many as 27 percent of the children in Virginia's foster care system in 2004 were sent voluntarily by parents or guardians to make them eligible for taxpayer-funded treatment, according to a report by the Virginia State Executive Council for the Comprehensive Services Act.

"I think the number is kind of shocking," Fralin said.

Tim Harris of Roanoke County signed an agreement giving up custody of his daughter Amy in 2004 so that she could receive mental health treatment that costs about $10,000 a month. His daughter, now 16, will soon be released next month from a hospital in Colorado, he said.

"I've never experienced such a frustrating and difficult set of circumstances," Harris said.

Harris said he had "virtually no say" in Amy's care or the decision to move her to three different hospitals.

"I tried to be involved in her care, and they wouldn't let me be involved," he said.

Asked about the attorney general's opinion, Harris said: "I only wish it had come three years ago."

A statewide child advocacy organization applauded McDonnell for clarifying the law.

"From this day forward, parents will no longer be confronted with the unconscionable choice of having to give up custody of their child in order to access mental health residential and other treatment," said Mary Dunne Stewart, the policy director of Voices for Virginia's Children.