The immediate impact of the ruling was not clear. Attorneys for the state Department of Education were reviewing the ruling, and home schooling organizations were lining up against it.

"Parents do not have a constitutional right to home school their children," Justice H. Walter Croskey wrote in a Feb. 28 opinion for the 2nd District Court of Appeal.

Noncompliance could lead to criminal complaints against the parents, Croskey said.

An estimated 166,000 students in California are home schooled, but it was not known how many of them are taught solely by an uncredentialed parent.

To earn a five-year preliminary teaching credential in California, a person must obtain a bachelor's degree and complete multiple examinations.

Until now, California allowed home schooling if parents filed paperwork to establish themselves as small, private schools; hired a credentialed tutor; or enrolled their child in an independent study program run by an established school while teaching the child at home.

The ruling stems from a case involving a Los Angeles-area couple whose eldest child reported "physical and emotional mistreatment" by the father, court papers said.

The father, Phillip Long, vowed to take the case to the state Supreme Court.

"I have sincerely held religious beliefs," he told the Los Angeles Times. "Public schools conflict with that. I have to go with what my conscience requires me."