Nearly 7,000 Virginia children whose families have opted to keep them out of public school for religious reasons are not required to get an education, the only children in the country who do not have to prove they are being home-schooled or otherwise educated, according to a study.

Virginia is the only state that allows families to avoid government intrusion once they are given permission to opt out of public school, according to a report from the University of Virginia’s School of Law. It’s a law that is defended for promoting religious freedom and criticized for leaving open the possibility that some children will not be educated.

While most states accommodate families with religious objections to public education through home-schooling laws — which require parents to report back on children’s academic progress with test scores and other benchmarks — or in three other cases, much more restrictive exemption laws, Virginia offers an additional option that gives families total control over their children’s education.

And more and more families are choosing that exemption, with an increase of more than 50 percent from the 2000-01 school year to last year, according to figures from the Virginia Department of Education.

Andrew Block, who is director of the Child Advocacy Clinic at U-Va., said it is good policy to respect the freedoms and beliefs of families. But after studying Virginia’s law, he concluded in a report that the state’s approach has many flaws.

“Given the numbers of kids involved, given the possibility that some kids are not getting any kind of education and the law can’t do anything about that,” Block said, “our hope is that policymakers will want to take a second look at it.”

Home-school advocates say the law is essential to preserving the rights of families who believe that any state control of their children’s education would violate the tenets of their faith. It takes on particular importance in the state where Thomas Jefferson helped define religious freedom as a bedrock principle for the country.

“They feel that their deity has given them that responsibility,” said Amy Wilson of the Organization of Virginia Homeschoolers. For such families, she said, to have to file paperwork and evidence of progress would put them in a crisis of conscience.

Block became interested in the statute years ago, when a teenager asked for help because her parents had requested a religious exemption from compulsory attendance when she was a little girl, and she later wanted to go to school. It wasn’t until Block and a research assistant began looking into the 1976 law that he realized it was unique.

Once parents in Virginia are granted a religious exemption, they’re no longer legally obligated to educate their children.

The statute does not allow exemptions for political or philosophical beliefs “or a merely personal moral code,” but the beliefs do not have to be part of a mainstream religion.

“We were surprised at how regularly the exemption is granted,” Block said. “School systems almost never deny it.” And, according to a survey of superintendents in the commonwealth, school leaders rarely have further contact with the families after granting an exemption.

In Fairfax County, which reported nearly 500 children who had been granted the religious exemption as of the 2011-12 school year, parents and children older than 14 must submit a letter explaining their religious beliefs, and letters of support vouching for the authenticity of their beliefs.

Steven Staples, executive director of the Virginia Association of School Superintendents, said that once families have written to the district to request the exemption, superintendents tend to honor the families’ wishes. “Most folks who choose religious exemption have some very strongly held beliefs that we want to respect,” Staples said.

Last year, there were 6,800 children granted a religious exemption in Virginia, according to the Virginia Department of Education. That’s in addition to the approximately 25,000 students who are home-schooled and whose parents, by law, are required to document that they are meeting state standards.

“We presume there is some kind of home instruction going on,” said Charles Pyle, a spokesman for the department, but “once a religious exemption is granted, there is no follow-up reporting.”

Scott Woodruff, senior counsel for the Home School Legal Defense Association, said, “There is periodically a spasm of worrying and fretting and anxiety, but there is no empirical reason to question the quality of education the children get.”

Several home-school advocates emphasized that they tell families that the choice is a responsibility, not just a right.

“This is a very serious decision, not something everyone should do,” said Yvonne Bunn of the Home Educators Association of Virginia. “It is based on sincere religious conviction. If that’s not the case, they need to just comply with the home-schooling law.”

Parents who seek the exemption, Bunn said, “would probably rather go to jail rather than put their children in school, because they have very strong convictions that they’re following what God has directed them to do.”