After 13 children, aged 2 to 29, were found in January, starved and shackled in a California home, some critics argued the abuse was missed in part because the children were being home-schooled.
But home-school advocates, across the nation and here in Chattanooga, vehemently deny the abuse was linked to the practice, while others say the lack of oversight or regulation of home-schooling leaves holes such as those where vulnerable children can easily fall through the cracks.
Tennessee law currently allows several different options for parents who want to home-school their children, with varying levels of autonomy.
Parents can register independently with their school districts, sending in documentation of their intent to home-school, attendance records and curriculum samples to local county school districts, or parents can register with church-related schools or independent private schools.
When registered with independent private schools, parents submit all documentation to those "umbrella" schools, which have the same minimal state oversight as other non-public independent schools.
In the case of the Turpin siblings, California treats home schools like other private schools and requires registration. Private schools are subject to annual fire inspections but no agency regulates or oversees them.
Some advocates argue this lack of oversight allows parents to hide abuse.
"There's no better way to isolate your child if you are an abusive parent than to home-school," said Rachel Coleman, executive director of the Massachusetts- based Coalition for Responsible Home Education, which maintains a database of home-school abuse cases.
The coalition lobbies for mandatory medical visits or academic assessments that would ensure home-schooled children are seen by someone trained to recognize abuse. Less than half of the U.S. states now require academic assessments, the Education Commission of the States said in a 2015 report on home-school regulations.
In Tennessee, students who are registered independently through their local county school districts are required to take mandatory state assessments, but only in grades 5, 7 and 9, according to the Tennessee Department of Education.
Students registered through a church-related or independent private school are not required to take state-mandated assessments. The number of students enrolled in such schools is also hard to pinpoint, state education officials say.
School districts are required to report how many students are being home-schooled each year - this year in Hamilton County, 281 home-school students are registered, according to district data.
However, independent, private schools report only their total attendance numbers to the state, which often includes students who actually attend on-site schools as well as those home-school students registered through the school's umbrella school, said Marcy Tidwell, the state education department's director of school choice.
Nationally, home-schooling advocates say they are bracing for calls for stricter oversight of the practice in light of the Turpin case. They support mandatory medical visits or regular academic assessments of home-schooled children.
But others contend moves to step up controls in the name of exposing child abuse earlier could lead to over-regulation and intrusion that punishes parents.
"Right now, the biggest threat is that lawmakers might make a decision based on the emotion of the moment, rather than looking at the empirical evidence," said Scott Woodruff, senior counsel with the Virginia-based Home School Legal Defense Association. He said national organizations that track risk factors for child abuse, including the U.S. Commission to Eliminate Child Neglect and Fatalities, don't list home-schooling among them.
One California lawmaker has floated the idea of requiring annual walk-throughs of home schools by state or county officials because of the case and "a number of legislators have expressed interest in doing something," the Home-School Association of California said in a statement.
"We can't prevent evil," the association said, "and trying to prevent it by taking away the freedom of law-abiding people is not a price our society should pay."
Tennessee's Department of Children Services does not track where reports most often come from, said spokesman Rob Johnson.
State law requires the department to keep the identify of someone making a referral to DCS confidential. Referrals often come from law enforcement, schools and other professionals, but can also come from community members, relatives and neighbors.
Some parents worry families that home-school are stereotyped as controlling or ultra-conservative.
Wendy Murphy, a Marion County mother who home-schools her two children, was apprehensive at first about doing so.
"I had always been against home-schooling," she said. "They only kids I knew wore the long dresses, hair up and that was not the way I was raised."
Murphy decided to home-school her 11-year-old son, Jaxson, halfway through his second grade year in Alabama.
"It was a personal education choice for us," Murphy said. "He was so far ahead of the other kids, I asked the school 'Can we advance him a year,' and they kept telling me that in second grade they would test him to see if he could go on to gifted classes in the third grade so I let him go half of the second grade year, but he was crying everyday because he was bored."
Murphy, who also has a 9-year-old son, pays $135 a year per child to Gateway Christian School, an umbrella school.
In Alabama, she also used an umbrella school, but Alabama regulates home-school students even less than Tennessee.
In Alabama, "the Department of Education has virtually no regulation or authority over home-schoolers," said spokesman Michael Sibley. "The same is true of private schools in the state. The Alabama College and Career Ready Standards are there as a minimum standard guide for instruction, but there is no mandate or legal obligation for home-schoolers and/or private-schoolers to report to the Alabama Department of Education."
The Georgia Department of Education has a similar lack of oversight or responsibility of home-school students. This school year, 64,463 students are considered to be home-schooled, according to state data.
Georgia requires parents or guardians to submit a declaration of intent to home-school by Sept. 1 of each year. Parents are also required to provide instruction in math, English language arts, sciences, social studies and reading and must have at least a high school diploma or GED.
Tennessee also has basic educational requirements for parents who teach their children - parents are required to possess a high school diploma or equivalent if they are registered independently and educating children in ninth grade or higher. Parents registered through an umbrella school have no such requirement.
"Tennessee's home-school law is one of the most complex in the nation," claims a 2012 report released by the Tennessee Comptroller of the Treasury's Office of Research and Education Accountability. According to that report and the Home School Legal Defense Association, Tennessee is recognized as a state that has "moderate" regulation - 17 other states have the same.
According to attorney Dan Beasley, who oversees Home School Legal Defense Association's work in Tennessee, more people are turning to home-schooling.
"It's seeing a trend certainly," he said. "It's grown substantially across the state in the past 10-20 years, my sense is it probably is thriving."
In recent years, the trend in state laws has been toward loosening government oversight of home-schooling, said Joseph Murray, a Vanderbilt University education professor who has researched home-schooling. West Virginia, for example, in 2016 reduced the number of annual assessments parents must submit to the district, and Arkansas eliminated an academic assessment requirement in 2015.
"There are states now where you don't really have to do anything. You don't even have to notify anybody that you're home-schooling," Murphy said.
Recent nationwide efforts to put more controls on home-schooling at state levels have largely failed.
Kentucky legislators declined to consider a 2017 bill introduced after an 8-year-old home-schooled girl was tortured by her father and his live-in girlfriend that would have barred families with histories of child abuse from home-schooling.
After two home-schooled children were found dead in a Detroit freezer, a 2015 Michigan bill would have required documented meetings with a teacher, doctor or clergy. The bill stalled in a legislative committee.
In Iowa, a bill requiring quarterly checks of home-school students was introduced in 2017 after a home-schooled teen starved to death. It, too, remained in committee.
And in Kansas, a grandmother unsuccessfully pleaded for stricter home-school control in 2015 after her 7-year-old home-schooled grandson was starved and killed by his father, who fed his body to pigs.
In the California case, authorities have said the 13 children of David and Louise Turpin - ranging in age from 2 and 29 - were rescued Jan. 14 from a home that looked well-kept on the outside. But authorities said children were kept chained to beds for months and some were so malnourished their growth was stunted. The parents have pleaded not guilty to torture, abuse and other charges.
In Tennessee, the Home School Legal Defense Association is not currently tracking any legislation regarding home-schooling regulations, Beasley said.
Nationwide legislation in light of the California incident is hasty, cautions Beasley.
"We think these efforts assume home-schooling is the problem," he said. "We think hasty legislation is unfair to the thousands of law-abiding home-school families."
Staff writer Meghan Mangrum contributed to this report.